[PERF] Skip resolving if Gemfile has not changed
Cherry pick perf fix from master
Fix bug involving source ordering and pinning
it turns out we only care if they are the same
fix backwards change-detection logic

pairing with @wycats and @indirect
turns out arrays are sensitive to order
unlock when gems are added to a path
slightly less obtuse than carl
update changelog for 1.1.rc.8
Version 1.1.rc.8
fix the changelog date
Merge branch '1-1-stable'

Conflicts:
	lib/bundler/definition.rb
	lib/bundler/source.rb
	spec/bundler/dsl_spec.rb
reset @gemspec_cache for tests

Bundler.load_gemspec now caches specs, which will break tests since the
new gemspecs won't be loaded. We don't want them to be cached for tests.
instance_variable_set is ugly, turn it into a method
support post_install_message when using the endpoint
support post_install_message when using the endpoint
update changelog
fix 1-1-stable merge (for 1.1.rc.8)
prevent duplicate sources
#1694: add failing test for duplicate git sources