Updated travis build scripts (from rspec-dev)
Merge pull request #1809 from rspec/update-travis-build-scripts-2014-12-17-for-master

Updates from rspec-dev (2014-12-17)
Fix intermittently failing specs.

These specs would fail when run in isolation but
would pass when run after other specs that used the
`match` and `include` matchers first (causing them
to be loaded). To make them consistently pass,
we need to get the matchers before manipulating
the load path to ensure they are already loaded.
Merge pull request #1810 from rspec/fix-spec-that-replace-the-load-path

Fix intermittently failing specs.
Refactor specs to not use private config API.

`config.include_extend_or_prepend_modules` is an internal
API that I plan to change in an upcoming commit.
Remove spec for behavior we will no longer be supporting.

Fully supporting metadata mutation is fraught with difficulties
see (rspec/rspec-rails#829 and the attempted fix in #1089).
For RSpec 3, we decided to expose `define_derived_metadata`
as an officially supported way to accomplish the sorts of
things metadata mutation was used for in RSpec 2. This spec
got left behind (since it was passing at the time, it wasn't
noticed) but isn’t something we want to support going forward
since module inclusion shouldn't mutate metadata. It’s also
getting in the way of a perf optimization I'm implementing.
Reify new FilterableItemRepository abstraction.
Refactor config metadata filtering to use new FilterableItemRepository.

This should perform better.
Benchmark stubs.
more benchmark attempts