change EXE names in demo makefiles
Merge branch 'Vogtinator-master'
always link demos with a local build of Nspire I/O instead of the Ndless SDK one
change DISTDIR of demos
fix wrong character count when no text is entered
- check return values of some syscalls (fixes #3)
- change includes
- remove old registry files
fix "tests" demo
Fix demo Makefiles