treat TerminationRequest as SystemEvent

TerminationRequest < SystemEvent, so the 'instance_of?' is a mistake.
Use Windows NUMBER_OF_PROCESSORS for Cygwin
Merge pull request #413 from douglaswth/use_windows_number_of_processors_for_cygwin

Use Windows NUMBER_OF_PROCESSORS for Cygwin
Merge pull request #412 from chronomantic/avoid_raise_wtf

treat TerminationRequest as SystemEvent
More detailed error message on unexpected message type

This error throws from time to time in our specs. We suspect it's a race condition, but it'd be nice to have some more detail in the message when it fires.
Merge pull request #414 from bluepojo/patch-1

More detailed error message on unexpected message type
2.1.0 -> 2.1.1 on Travis
give better rspec messages by using default stubs
rework core detecting + refactor tests

  * avoid setting @cores if it's going to be returned anyway

  * handle exception when NUMBER_OF_PROCESSORS is empty string

  * handle *BSD group along with Dragonfly BSD

  * use IO.read + exception handling instead of File.exist?

  * group tests by os type

  * support using NUMBER_OF_PROCESSORS to override detection on EVERY os

  * test showing error (stderr)

  * use sysctl '-n' parameter to make things more robust

  * remove CELLULOID_IGNORE_CORE_COUNTING_ERRORS and error handling
Merge pull request #415 from chronomantic/rework_core_detecting

Rework core detecting
CPU counting fixups
Add PoolManager#size= to allow for on-the-fly adjustment of pool sizes
Terminate detached workers
map the futures, not the actors themselves
Merge pull request #417 from cheald/pool_shutdown_fix

Map the futures during Pool#__shutdown__, not the actors themselves
Merge pull request #416 from cheald/adjustable_size_pools

Add PoolManager#size= to allow for on-the-fly adjustment of pool sizes