Optimized bump.sh

* allow user to call script from everywhere
* made sed work on Linux and OS X

Fixes #342
Merge remote-tracking branch 'upstream/master'
minor optimizations to TinkerMessenger.
Added transparency/feathering to batch-graph logo.
Merge remote-tracking branch 'origin/master'
Merge pull request #348 from dkuppitz/master

Optimized bump.sh
TinkerPop 3.0.0.M6 release