Improved error handling in variables-related commands.

Improved error handling in variables-related commands.

exprlong() and exprboolean().

exprlong() and exprboolean().

requires at least Mac OS X 10.6.

get_magic->util.MAGIC_NUMBER, source_from_cache, and cache_from_source.

Turns out I committed a work-in-progress entry because of a time
gap between when I wrote it and when I committed.

from the old green snake to the new new blue and yellow snakes.

from the old green snake to the new new blue and yellow snakes.

* Add a new asyncio.subprocess module
* Add new create_subprocess_exec() and create_subprocess_shell() functions
* The new asyncio.subprocess.SubprocessStreamProtocol creates stream readers
  for stdout and stderr and a stream writer for stdin.
* The new asyncio.subprocess.Process class offers an API close to the
  subprocess.Popen class:

  - pid, returncode, stdin, stdout and stderr attributes
  - communicate(), wait(), send_signal(), terminate() and kill() methods

* Remove STDIN (0), STDOUT (1) and STDERR (2) constants from base_subprocess
  and unix_events, to not be confused with the symbols with the same name of
  subprocess and asyncio.subprocess modules
* _ProactorBasePipeTransport.get_write_buffer_size() now counts also the size
  of the pending write
* _ProactorBaseWritePipeTransport._loop_writing() may now pause the protocol if
  the write buffer size is greater than the high water mark (64 KB by default)