Everything is merged to one repository; separation on ant task level

I have merged everything to one repository. Everything that is not subscript core is contained under src/subscript-extras. ```ant quick.subscript``` now builds only subscript core. The extras under subscript-extras are compiled using ```ant quick.subscript-extras```, presumably to build/quick/classes/subscript-extras. Core compiles without problems. Extras don't compile.
Also, it is possible to compile the extras using abt, because they are stored in the form of abt projects. This doesn't prevent ant from doing its job.