Moved prog check, so we can do color output
Made astyle step optional
Fixup: Merge two checks into one
Add typedef for selection functions
Added ll_select() interface and implementation
Added avl_select() interface and file for impl.
Added interface for ht_select() and impl file
Redefine r_set_select()
Add implementation for r_set_select()
Merge pull request #223 from matthiasbeyer/implement-r_set_select

Implementation of r_set_select()
Merge pull request #264 from matthiasbeyer/make_astyle_optional

pre-commit: Make astyle step optional
Fixed missing const modifier
Implemented ll_is_subset
Implemented ll_equal
Implemented avl_is_subset
Implemented ht_equal
Implemented r_set_equal
Added files to CMakeLists
Added ll_equal and ll_is_subset tests
Added avl_is_subset tests