Implemented "First" and "FirstOrDefault" operations#357

Merged

benjchristensen merged 4 commits intoReactiveX:masterfrom jmhofer:first-firstDefault

Sep 10, 2013

+564

Commits on Sep 7, 2013

implemented skipWhile and skipWhileWithIndex (ReactiveX#80 )
jmhofer
committed

Commits on Sep 8, 2013

Added the two variants of the first operator.
jmhofer
committed
Added FirstOrDefault operation
jmhofer
committed
Added link urls to the msdn descriptions
jmhofer
committed