(fact-81) Use Emit.dump rather than to_plist

See https://github.com/puppetlabs/facter/pull/499 and the linked
redmine tickets for backstory. The basic issue here is that
CFPropertyList monkey-patches some core ruby classes with a
to_plist method, which defaults to returning binary data. This
code was originally written to the vendored CFPropertyList
previously included in facter (but unvendored in fact-94),
which provided a different to_plist implementation returning
text data.

This commit avoids the conflicting to_plist implementations by
calling its own dump method, thus no change in behavior.
(maint) Reset facter search path when resetting facts

The previous implementation of Facter search paths was only additive and
there was no way to remove Facter search paths once added. This is
especially problematic when running the Puppet specs which wind up
reloading Facter frequently and adding search paths, and can wind up
adding thousands of meaningless paths. This commit resets the Facter
search path on `Facter.reset` so that when facts are reset, the known
search pats are reset as well.
Merge pull request #625 from kylog/issue/fact-81/avoid-multiple-impls-of-to_plist

(fact-81) Use Emit.dump rather than to_plist
(FACT-321) Remove interpreter arg for command execution
(FACT-321) Remove interpeter arg from resolution
(FACT-321) Remove deprecated interpreter from resolution
(FACT-321) Remove deprecated 'memorytotal' fact
(FACT-321) Remove deprecated Resolution#to_s()
(FACT-321) Remove ENV['DESTDIR'] and --test from install.rb
(FACT-321) Remove deprecated windows shell builtin execution
(FACT-321) Remove deprecated file extension expansion

This commit removes the automatic expansion of Windows commands that
have an absolute path but do not have a file extension.
(packaging) Update FACTERVERSION to 1.7.5
Merge tag '1.7.5'

1.7.5

* tag '1.7.5':
  (packaging) Update FACTERVERSION to 1.7.5
Merge pull request #631 from adrienthebo/maint/facter-2/remove-deprecations

Maint/facter 2/remove deprecations
Merge branch 'facter-2'
Merge pull request #628 from adrienthebo/maint/facter-2/cleanup-search-path-on-reset

(maint) Reset facter search path when resetting facts
Merge branch 'facter-2'