Make scripts executable

[krystiancha]

Scripts in scripts/ had mode 644 set, which made them non-executable.
This commit sets the mode to 755.

This resulted in errors like:

$ make lua
make base CTEX=lualatex OUT=build/lualatex
make[1]: Entering directory '/home/user/Downloads/WUT-Thesis'
make[1]: ./scripts/texenv.sh: Permission denied
# ... successful compilation but wrong resulting filename

and

$ make release
./scripts/make-release.sh
make: ./scripts/make-release.sh: Permission denied
make: *** [Makefile:45: release] Error 127

[ArturB]

Zgoda, wrzuciłem już na repo odpowiednie zmiany dodając do tego jeszcze jeden skrypt.
Dzięki za zwrócenie uwagi.