Include exception message in bacon error output
Make _spec suffix optional when running `rake spec files=...`

With this change, the following invocations are equivalent:

    rake spec files=integration_spec

and

    rake spec files=integration
Merge pull request #68 from thefrontiergroup/display_exception_messages

Include exception message in bacon error output
Merge pull request #71 from kastiglione/succinct-spec-files

Make _spec suffix optional when running `rake spec files=...`
add :force_load option into configuration of `app.vendor_project'

There are 3rd-party library which would trigger "duplicate symbol" error at compile time.
It will be useful in such libraries when specify false in :force_load option.

When specify true in this option (by default), it behaves in the same manner as before.

Usage:
    app.vendor_project('vendor/OAuth2Client',
      :static,
      :force_load => false,
      :headers_dir => 'Sources/OAuth2Client'
      ....
pass "-ObjC" flags to linker to load Objective-C class when "-force_load" is not used