Increased timeout for Eclipse tests. Fixed default settings.

Our root pom's tycho-surefire-plugin contained unnecessary
timeout configuration. It's better to rely on sure.timeout
and the tycho surefire plugin inherits that.
Eclipse tests have custom timeout of 3000 sec - the default
2400 was not enough on Mac (and Windows was getting close).
implicit waits in constructor added,
removed not needed workbench exceptions
Tree.getColumnCount() method implemented (tests included). Also column manipulation during tree tests updated a bit.
Missing API javadocs for Tree#getColumnCount() method
Implemented method getChildren() in ProjectItem
Implemented Navigator View #206