0.3.0 and async pool
added file handles test (thanks to Jochen Bedersdorfer!)
Added maxPoolSize configuration to documentation
Got rid of old helper classes (not needed with mod-scala 0.3.0 anymore)
Kicked unnecessary usedConnections queue + version in Readme.md
version update of underlying driver
Merge pull request #16 from vert-x/async-conn-pool

Switch to Scala 0.3.0 + async connection pool