Reduces memory consumption in stream pubsubs.

The XP route objects were being unneccesarily created for every publish
action, the object is now created during instantiation and simply
referenced during the lifespan of the publisher. This eliminated some
leakiness.
Merge pull request #211 from lukecampbell/streampub

Reduces memory consumption in stream pubsubs.
Adds OrderedSet to pyon utils
Adds unit test for OrderedSet
Merge pull request #212 from lukecampbell/orderedset

Adds OrderedSet to pyon utils
Fix extended resource unit test
Merge pull request #213 from shenrie/master

 Fix extended resource unit test
Print greenlets to stderr/file on SIGUSR2

With -n, output to stdout/stderr is blocked, so also dumps to a file ("gls-<pid>") on USR2.
Print PID in startup line
Made verbose repr for Endpoints be split over newlines