skip top frames in stack trace to fix memory leak

This fixes Moose::Exception leaking. The stack frames include all of the
arguments of each function call. Previously, some of the frames would be
method calls on the exception object, and so would include the object itself
in the arguments. This would create a reference loop, leaking the exception
object until process termination. Instead, we skip the stack frames related to
building the object, and only include those from ->new onward.

closes #81.
enforce version requirement in code where it is needed
exercise the Moose::Exception/Devel::StackTrace leak
explain what this block of code is doing
remove redundant version requirement
changelog for exception object leak
bump next version to 2.1213
changelog for Moose-2.1213
Merge branch 'stable/2.12'

Conflicts:
	Changes
	dist.ini
bump next version to 2.1304
oops, fix this new git code
changelog for Moose-2.1304-TRIAL
Make Moose::Exception stringification eliminate internal Moose & CMOP frames at top of trace by default

If the MOOSE_FULL_EXCEPTION env var is true these frames are included.

This doesn't affect the frames that are actually captured, just the stringification.
Doc updates for exception class & manual
Fix some tests of exceptions to check for the actual error message we care about

The test was checking for one word that appeared in the trace rather than the
specific error message we expect to be thrown.
Merge pull request #82 from moose/topic/less-moose-in-errors

By default, exceptions now eliminate most of the Moose internals from stack traces
remove build configs that did nothing

- GatherDir.exclude_match only works on base filenames, not directories
- Gatherdir.include_dotfiles defaults to false
- there is no MANIFEST.SKIP file for [ManifestSkip] to process
fix typo causing test to not be gathered
remove unused imports
dramatically speed up builds in uncleaned directories by not gathering old build dirs and their contents