Adds new methods into Utils class:
 - shorten(String, int) for shortening long strings, and
 - join(String[], String) for joining arrays of strings into one string

Also tests for Utils are added.
Tree.getColumnCount() method implemented (tests included). Also column manipulation during tree tests updated a bit.
Missing API javadocs for Tree#getColumnCount() method
Allows BroserView to use already existing InternalBrowser instance
Allows turning debugging on or off
Missing API doc
Merge branch 'Utils' into trunk
Merge branch 'trunk' of github:happz/reddeer into trunk