Use the correct date

I always intended for the date to be the *commit* date, not the *author*
date; I just never noticed the mistake until now.

More 1.8 compatibility

GVB.commit_date_version

This allows you to use an alternate, non-tag-based, approach for your
package versioning, if semver doesn't make sense for your application.  I
don't recommend it for general use.

Boneheaded bug fix release

Begone, evil `Errno::ENOENT: No such file or directory @ realpath_rec`!

Backwards compatibility ftw

This release just re-implements `Gem::Specification#lib_dirs_glob`
internally, using features that were added to Rubygems a decade ago, for
people who are using *very* old versions of Rubygems.

Bugfixes: the UnwashedMeme edition

Fixed a typo and 1.8 compatibility problems.  Thanks to @UnwashedMeme for
the patches.

Ruby 1.8 compatibility fixes

May as well maintain it, while we can.

Fix 'Version is now' output

One more place I needed to pass 'true' into GVB.version...

Other projects have versions too, you know

This release changes the API by re-adding an optional argument to
GVB.version and GVB.date, to tell them to not do anything clever (looking in
the call stack) to find out who's calling, but instead only look in the
local git tree.  This is needed for git-version-bump (the binary) to
recognise versions other than GVB's own.

The "robustness" release

Hopefully less unwanted exceptions will be raised, however some more useful
exceptions may be raised instead.