- Added regression test with queries over the WORLD database.
- Discovered and fixed several bugs in the related cost calculation
  functionality both in the semijoin and non-semijon subquery code.
- Added DBUG printing of the cost variables used to decide between
  IN-EXISTS and MATERIALIZATION.

- Remove garbage comments

introduced at the latest merge 5.1->5.2->5.3.
It is basically not needed since if SQL_SELECT::pre_idx_push_select_cond 
is not NULL then SQL_SELECT::original_cond would point to the same condition
as SQL_SELECT::pre_idx_push_select_cond. Otherwise SQL_SELECT::original_cond
would be equal to SQL_SELECT::cond.

The fix blocks execution of any constant sub-expressions of
the defining expressions for virtual columns when context
analysis if these expressions is performed.

Fixed a compiler warning.

- Code cleanup: remove garbage comments

- Don't call table_list->process_index_hints() for JTBM pseudo-tables
- Update test results

- bad .result merge
- make .test file do not switch off both materialization and IN->EXISTS as that leads to error now.

- Update test results (checked)
- Fix compiler warning

way of processing prepared statements:
- conversion subquery_predicate -> TABLE_LIST is once per-statement
- However, the code must take into account that materialized temptable
  is dropped and re-created on each execution (the tricky part is that 
  at start of n-th EXECUTE we have TABLE_LIST object but not its TABLE object)
- IN-equality is injected into WHERE on every execution.

Also, change windows timespec definition to be Unix-ish - simplifies handling a lot.

A lot of small fixes and new test cases.

client/mysqlbinlog.cc:
  Cast removed
client/mysqltest.cc:
  Added missing DBUG_RETURN
include/my_pthread.h:
  set_timespec_time_nsec() now only takes one argument
mysql-test/t/date_formats.test:
  Remove --disable_ps_protocl as now also ps supports microseconds
mysys/my_uuid.c:
  Changed to use my_interval_timer() instead of my_getsystime()
mysys/waiting_threads.c:
  Changed to use my_hrtime()
sql/field.h:
  Added bool special_const_compare() for fields that may convert values before compare (like year)
sql/field_conv.cc:
  Added test to get optimal copying of identical temporal values.
sql/item.cc:
  Return that item_int is equal if it's positive, even if unsigned flag is different.
  Fixed Item_cache_str::save_in_field() to have identical null check as other similar functions
  Added proper NULL check to Item_cache_int::save_in_field()
sql/item_cmpfunc.cc:
  Don't call convert_constant_item() if there is nothing that is worth converting.
  Simplified test when years should be converted
sql/item_sum.cc:
  Mark cache values in Item_sum_hybrid as not constants to ensure they are not replaced by other cache values in compare_datetime()
sql/item_timefunc.cc:
  Changed sec_to_time() to take a my_decimal argument to ensure we don't loose any sub seconds.
  Added Item_temporal_func::get_time() (This simplifies some things)
sql/mysql_priv.h:
  Added Lazy_string_decimal()
sql/mysqld.cc:
  Added my_decimal constants max_seconds_for_time_type, time_second_part_factor
sql/table.cc:
  Changed expr_arena to be of type CONVENTIONAL_EXECUTION to ensure that we don't loose any items that are created by fix_fields()
sql/tztime.cc:
  TIME_to_gmt_sec() now sets *in_dst_time_gap in case of errors
  This is needed to be able to detect if timestamp is 0
storage/maria/lockman.c:
  Changed from my_getsystime() to set_timespec_time_nsec()
storage/maria/ma_loghandler.c:
  Changed from my_getsystime() to my_hrtime()
storage/maria/ma_recovery.c:
  Changed from my_getsystime() to mmicrosecond_interval_timer()
storage/maria/unittest/trnman-t.c:
  Changed from my_getsystime() to mmicrosecond_interval_timer()
storage/xtradb/handler/ha_innodb.cc:
  Added support for new time,datetime and timestamp
unittest/mysys/thr_template.c:
  my_getsystime() -> my_interval_timer()
unittest/mysys/waiting_threads-t.c:
  my_getsystime() -> my_interval_timer()

CMake 2.8.4 crashed on this line
 IF(something AND IS_DIRECTORY(something_else))
when both  "something" and "something_else" were empty.

Changing the line slightly (using cascading "IF" instead)  solved the crash.

Disable call to setpriority() in pbxt. This caused mysqld to run with nice priority -19, which was far from optimal.

mysql-test/suite/innodb/r/innodb_bug60049.result:
  Updated results
mysql-test/suite/innodb/t/innodb_bug60049.test:
  Force global.innodb_fast_shutdown to 0 as test require it
mysql-test/suite/innodb_plugin/t/innodb_bug60049.test:
  Force global.innodb_fast_shutdown to 0 as test require it
storage/pbxt/src/pthread_xt.cc:
  Disable call to setpriority()

The error message is now based on GetLastError() rather than errno. 

Background: errno is C runtime specific and in many circumstances 
it is not set, e.g when using Win32 API or socket functions.

This simplifies postmortem analysis for crashes reported via Winqual.

HEAP is deprecated in favor of MEMORY.

mysql-test/suite/funcs_1/r/innodb_func_view.result:
  Updated results
mysql-test/suite/funcs_1/r/memory_func_view.result:
  Updated results
mysql-test/suite/funcs_1/r/myisam_func_view.result:
  Updated results
mysql-test/suite/pbxt/r/func_str.result:
  Updated error numbers
mysql-test/suite/pbxt/r/type_newdecimal.result:
  Updated error numbers
mysql-test/valgrind.supp:
  Added suppression for warning on Work (OpenSuse 11.3 64 bit)

mysql-test/r/subselect4.result:
  Moved test case for LP BUG#718593 into the correct test file subselect_mat_cost_bugs.test.
mysql-test/t/subselect4.test:
  Moved test case for LP BUG#718593 into the correct test file subselect_mat_cost_bugs.test.

unix_timestamp() and time_to_sec() are hybrid items,
  returning integer or double depending on the argument.