added BlockElement class as Scratch block abstraction (#GSOCSTCC-32)
moved common and test functionality
fixed Script validation
removing failing assertion in windows
enable determinstic wav conversion
corrected test project name
adding command-line interface, adding support for conversion from folder
added block abstraction subtypes, renamed base class (#GSOCSTCC-32)
fixed class hierarchy

* changed: Object superclass for RawProject
* removed: unnecessary code
* added: error handling
extend TemporaryDirectory
cleaned import, function name; removed unused code
refactored blocks converter based on Scratch block hierarchy (#GSOCSTCC-32)

* added: additional converted blocks / fixed blocks
* removed: explicit naming of unsupported blocks
* added: functionality to Catrobat
extracted new class for converted project saving (#GSOCSTCC-32)
added class for Scratch conversion beginning with Objects (#GSOCSTCC-32)
added top level Scratch converter class (#GSOCSTCC-32)

* added: preproccesing step (currently just for a workaround)
little cleaning
Merge branch 'master' of ssh://github.com/Catrobat/ScratchToCatrobat