gitignore: be more clever
Merge pull request #395 from matthiaskrgr/install_deps

install-deps.sh: arch: wording changes
Merge pull request #398 from matthiaskrgr/gitignore

gitignore: be more clever
build_make_clean.sh: also make clean in build_cef, if existing.
Merge pull request #400 from matthiaskrgr/build_make_clean

build_make_clean.sh: also make clean in build_cef, if existing.