Some small speedups


Docs/manual.texi:
  Changelog
client/mysqldump.c:
  Fixed quoting problem for table names when using --opt
mysys/mf_casecnv.c:
  Speed up some common string functions
sql-bench/test-insert.sh:
  Small changes that shouldn't affect results
sql-bench/test-select.sh:
  Small changes that shouldn't affect results
sql/field.h:
  Added reset() functions to speed up some common things
sql/gen_lex_hash.cc:
  Smaller hash table
sql/ha_innobase.cc:
  Fixed bug in auto-increment handling with InnoDB