Foolproof debundle

Gem::Specification.reset is not enough, since it would pick up the same GEM_HOME which was set by bundler. So we need to restore it first, then clear gem paths (to pickup a change in ENV) and then continue with previous hack.
Merge pull request #9 from brainopia/patch-1

Foolproof debundle
bump version
adjust readme
move around files
remove references to pry from debundle.rb
v0.7.d
tweak readme
further readme tweaks