improve documentation
Merge pull request #52 from pointhi/master

improve documentation
improve build.xml
fix bug inside InitMenuBar.java
add virtual display for testing
throw error if build, test or run failed
Merge pull request #53 from pointhi/master

* add gui tests and fix test conditions
* fix bug in gui
save line of var and con declaration
Merge pull request #55 from pointhi/master

save line of var and con declaration
Merge pull request #56 from fabian1995/master

Bugfixes and some useful features