Merge pull request #31 from somdoron/master

fix collection was modified exception and performance improvement issue #30 and issue #26
Update README.md
Initial implementation of devices
Merge pull request #33 from somdoron/master

tcp keep alive
Merge remote-tracking branch 'upstream/master' into devices
Added SocketSetup for devices.
Refactored the device tests to make it a bit simpler to manage.
The forwarder device should now work.
Devices can take a Poller instance as a parameter, so pollers can be reused.
Merge pull request #35 from reiroldan/devices

Initial implementation of devices
working pgm implementation.

still need to cleanup code. write tests, test with original zeromq openpgm and finish interface part of the address.
Merge pull request #36 from somdoron/master

remove pinvoke, fix issue #34
pgm development completed. unit testing in place as well.

differences from zeromq pgm
* it uses ms-pgm (msmq pgm)
* loopback is supported (actually cannot be disabled)
* epgm is not supported (using epgm in the transport will use pgm)
add a test for large message
Merge pull request #37 from somdoron/PGM

Pgm completed. solve issue #9
Update README.md
add cancel socket to the poller
Update README.md
Update README.md
Update README.md
Merge pull request #41 from somdoron/Poller

add cancel socket to the poller
there was wrong calculation of ms to us, fixed that