Delay root actor initialization

so it does not force global_task_initialization
Merge pull request #124 from ruby-concurrency/actress

Delay root actor initialization
Fix typo
#126
#126
Merge pull request #127 from maximchick/master

warning: ambiguous Java methods found
"num_threads" should be "overflow_policy" as the former is unused
Merge pull request #129 from sheaney/chore/clean_up

"num_threads" should be "overflow_policy" as the former is unused
Added Glitter basge to README
Updated maintainers and contributers in the README
Upgraded to RSpec 2.99
Ran transpec with RSpec 2.99 but now have 29 failing specs.
Upgraded to RSpec 3.0. Now have 26 failing tests.
Fixed broken Obligation specs.
Fixed broken Actress specs.
Merge pull request #128 from ruby-concurrency/refactor/rspec3

Upgrade to RSpec 3.0
Released v0.7.0.rc1 (Release Candidate 1).
Restored original experimental CAtomicBoolean.
Rewrote CAtomicBoolean based on CAtomic.
Rewrote CAtomicFixnum based on CAtomic.