Speed up CI builds by caching gem dependencies in S3
Use bash to verify that there were no Ruby syntax warnings
Avoid Ruby verbose mode syntax warnings in the test suite
Globally set `--backtrace` flag for RSpec/Cucumber in CI
Cleanup test tasks in Rakefile
Remove the rspec-1 submodule

It costs us ~3s in each CI build, its hook in cucumber is clunky, the
test that is supposed to assert compatibility with RSpec 1 is broken,
and I think we could drop support for something that's almost 5 years old.
Skip Bundler and Rubygems while executing ruby scripts in cukes

Speeds up subprocess execution by preparing the LOAD_PATH for nested
interpreter invocations. Some attempt to do this existed previously but
it wasn't efficent and did rely on Rubygems nevertheless.

Bundler is only used for subprocesses that need to invoke gem binstubs
such as `cucumber` and `rspec`. Such cukes are tagged "@with-bundler".
Speed up cukes by having Aruba wait less for IO

The default was 100 ms. Leave that default for JRuby.

Seems like 5 seconds isn't enough on CI:
https://travis-ci.org/vcr/vcr/jobs/37566372

Ruby 2.0.0 fails pretty consistently if timeout is around 10s or less:
https://travis-ci.org/vcr/vcr/jobs/37569992

Of course, I have no idea why.
Avoid Cucumber deprecation notice
Tweak the local server used for testing
Randomize test server ports in cukes

Previously, cukes typically used ports 7777 and 8888 for spinning up the
Sinatra test server. This would fail when the user already has something
running on one of these ports, like Charles proxy which typically runs
on 8888.

Now the ports are randomized and picked based on availability. This also
means that there is no chance of port collisions in the condition when
one subprocess is shutting down a server while the other is starting a
new one.
Don't fail the CI build if simplecov segfaulted. It happens often
Add `script/test` for running individual files/directories
Enable Travis folds in CI output
Output timing information per test operation in Travis web interface
Add missing return to `fold`.
Merge pull request #440 from vcr/here-lies-mislav-tried-to-fix-ci

Attempt at better CI speed and stability