Removed unnecessary PATHS from cmake modules

- DEPS_INSTALL_DIR is already set into CMAKE_PREFIX_PATH in
  the main CMakeLists.txt
Merge #910 'Remove unnecessary PATHS from cmake modules'
Split f_feedkeys into a separate feedkeys function

- This commit separates the feedkeys logic from the vimscript
  checks in preparation for using feedkeys() in C code.
Make vim_feedkeys a simple wrapper around feedkeys

- To clean up the mix between feedkeys and replace_termcodes
  the vim_feedkeys API functions now does the same thing as the
  vimscript feedkeys() function
Add API vim_replace_termcodes

- Add API function to call replace_termcodes
Fix wrong ptr check for vim_replace_termcodes