set $MANPATH in Bundler::Runtime#setup_environment

This lets `bundle exec man ...` show man pages from bundled gems.
Add ENV[DEBUG_RESOLVER_TREE] which outputs the resolver tree when bundle install.
Add a spec for issue #2124 (I think)
Fix for issue #2124

 - don't complain if local_override being updated anyway
Arguably a cleaner fix for issue #2124
Note change in changelog
silence resolver during show
Fix gem_helper_spec.

Fixes "Bundler::GemHelper tasks gem management release releases even
if tag already exists", otherwise the test case fails with:

     RuntimeError:
       There are files that need to be committed first.
don't store dry-run as a setting
Version 1.3.2 with changelog
don't actually need USE_PERSISTENT
extract Fetcher::SSLError
include rubygems.org CA chain, add settings

Bundler.settings[:ssl_verify_mode] and Bundler.settings[:ssl_ca_cert]
are now both available. ssl_ca_cert accepts either a file path or a
directory, and will add either one correctly.
update changelog
exclude certs from quality spec
use YAML.dump over {}.to_yaml, thanks @tenderlove
Version 1.3.3
update changelog
remove quotes on RUBYOPT on Windows
Welcoming @jlsuttles to Bundler Core! \o/