0.7.1alpha1

Improvements::

* runtime/ide: detect and handle CTRL-C breaks
* ide: handle workbench startup + argument
* ide: create icons for source code files and binaries
* compiler/runtime: String concatenation implemented
* compiler: SLEEP FOR statement added
* runtime: workbench startup code added
* runtime: auto-open WINDOW 1 on first text output in debug/worbench startup mode

Bug Fixes::

* compiler: CLI return code fixed
* compiler: handle varPtr in BinOp expressions
* compiler: reset compiler options on each compiler run
* ide: do not crash if non-existing file is specified as cmd line argument
* ide: fix refresh while program is running
* runtime: fix _aqb shutdown crash
* runtime: fix INKEY buffer handling
* runtime: fix TIMER nullpointer access