Basic test for instrumentation loading

Inspired by how we swallow failures during dependency detection to keep from
crashing, this basic test checks for errors when running detection with nothing
but the agent present.

This certainly won't catch every dependency detection failure, but it covers
the top-most level of each defer working when the dependencies in question
*aren't* available.
Make thread profiling multiverse test less flaky

Two issues being addressed here:

1. There was a race in the way that the test_thread_profiling and
   test_thread_profiling_with_pruby_marshaller tests were set up. We were
   starting the thread profiler and *then* starting the two threads it was
   supposed to take samples of, and then waiting for at least 10 poll cycles,
   and asserting that we saw 10 samples. If the threads didn't have a chance to
   start up before the first few poll cycles, this wouldn't work.

   We now start the threads to be profiled before starting the thread profiler,
   and ensure that they've actually executed the block passed to run_thread
   before proceeding.

2. The profiled threads would sleep for 10s, and then exit. If the test took
   longer than 10s, this wouldn't work. Now they will sleep indefinitely, until
   explicitly woken from the call to Thread#run from join_background_threads.
Merge pull request #334 from newrelic/thread-profiling-khan

Make thread profiling multiverse test less flaky
Merge remote-tracking branch 'origin/release' into dev
RUBY-1249 Don't break ability to pass a URI to Typhoeus (in versions 0.6.4+)
Now that we've dropped support for Ruby 1.8.6, update to mocha 0.14.0
We don't need to call before_setup/after_setup explicitly anymore - MiniTest will do so for us
Clean up ar_method_aliasing multiverse tests
Merge pull request #336 from newrelic/update-mocha

Update mocha to 0.14.0, paving the way for MiniTest 5 (and ultimately Rails 4.1 testing)
RUBY-1249 Fix version comparison in Typhoeus test
RUBY-1249 Don't needlessly ping-pong between URI and String for Typhoeus
Merge pull request #335 from newrelic/RUBY-1249

RUBY-1249 Don't break ability to pass a URI to Typhoeus (in versions 0.6.4+)
RUBY-1128 Convert Rails view instrumentation tests to a more standard form
RUBY-1128 Add a failing test case to demonstrate bad exclusive time in Rails 4 template rendering
RUBY-1128 Record exclusive time correctly for template rendering on Rails 4
RUBY-1128 Remove left-over pry reference in multiverse default Gemfile
RUBY-1116 Fix add_method_tracer usage when init_plugin has not been called
Initial work for running unit tests on minitest

This includes a significant number of changes to tests to root out order
dependencies, but probably hasn't caught them all.

It also doesn't appear to work right with Rails 3.0 in test:env yet, so that'll
be my bit of work to tackle on this.
Merge pull request #337 from newrelic/RUBY-1128

RUBY-1128 Record exclusive time for template rendering correctly on Rails 4
Fixed typo