Fixed outer skin layers not appearing (fixes #162).
Fixed swords stopping digging in Survival mode (fixes #349).
Consider world created before WorldLoadEvent is called.
Added Eclipse project name override to build script.

Intended to fix weirdness with importing the files generated by the
Eclipse gradle plugin.
Added snow block placement handling.
Added note about Trello to CONTRIBUTING.md.
Refactored out use of JSONObject in the protocol in favor of TextMessage.
Minor cleanup.
Networking unit tests

Signed-off-by: William Lebel <lebelwilliam@gmail.com>