wip: Initial import of ruby-atomic.
Fixed broken Java build.
Added legacy Atomic class with deprecation warning.
Triggering TravisCI build of atomic-reference branch.
Specs with native extensions passing on MRI, JRuby, and Rubinius.

Added fake_build hook back to extconf.rb
Atomic specs now defined by share_examples_for

wip: Updated atomic_spec to support platform-specific testing.
Atomic now extends platform-specific implementation; defaults to MutexAtomic.
Updated atomic benchmarks to test all available implementations.
Updated build tasks to support rake-compiler-dev-box

wip: Updates to suppoer rake-compiler-dev-box
First successful gem build using custom rake-compiler-dev-box.

Removed superflouous lines from gemsepc and Rakefile.

Fixed CAtomic load error for Windows cross-compiled extensions.
Gems built with new build boxes and tested no several operating systems.

C extensions added back to platform-independent gem.

Fixed platform-independent gem build.

Platform-independent build now works the way we intend.

Fixed package and build problems in Rakefile.

Better error messages.

Reduced the number of threads in atomic parallel tests.
Platform-neutral build no longer has native extensions.
Changed version number to 0.7.0.rc0
Merged 0.6.1 Actress updates into native Atomic branch.
Fixed post-merge problems with Travis CI and buld tasks.
Fixed post-merge problems with Travis CI and buld tasks.
Merge pull request #111 from ruby-concurrency/atomic-reference-with-actress

Atomic Reference with Actress