A logger is added.

It can be disabled during compilation as well.

Use goog.debug.Logger.getLogger('postile.foo.bar') to get a logger
for your module.
Merge remote-tracking branch 'origin/master'
Merge remote-tracking branch 'origin/master'
Finished issue #12

- Right-click drag on the post board is disabled.
- Cursor-over-edge scrolling of the post board is disabled.