added monitoring interface
take 2
automatically enable monitoring when required
reworked exposed api
use internal notifications system
provide an api call to start the probe "system"
added probe tests
reworked probe tests to get rid of timing issues
Raise on JRuby 1.7.3 warning Celluloid is broken

After helping someone debug this *again* today I think our best bet is
to simply have Celluloid raise if someone tries to require it on JRuby
1.7.3:

    $ bundle exec irb -rcelluloid
    RuntimeError: Celluloid is broken on JRuby 1.7.3. Please upgrade to
    1.7.4+
Merge pull request #307 from celluloid/blow-up-on-jruby-173

Raise on JRuby 1.7.3 warning Celluloid is broken
Specify full path for sysctl on darwin hosts
Merge pull request #308 from amrik/master

Specify full path for sysctl on darwin hosts
remove empty lines
probe refactor
Add guards for creating, suspending and resuming Tasks
Add a backtrace to the Task termination exception
Set the task status to running before raising the resumable error
Package entire specs with gem

Fixes #263
Merge pull request #311 from celluloid/task-terminate-backtrace

Add a backtrace to the Task termination exception
removed  reset from celluloid.rb