Option Refactor and addition of Zoom Rate (#589)

* fixed for simpler parenthesis matching

* absolute file path for .fehbg, moved script creation into helper function

* Removed unused variable.

* added early exit condition as per Ferada's suggestion

* Added enum for options to improve readability

* migrated options to enum.

* added support for zoom specification through options

* added man entry for zoom-rate

* added help entry for zoom-rate commands

* updated man to have warnings about strange values for zoom options

* fix memory leak (free exec_absolute_path)

* added detection for path vs env PATH launch for use in .fehbg script gen.

* Added enum for options to improve readability

* migrated options to enum.

* added support for zoom specification through options

* added man entry for zoom-rate

* added help entry for zoom-rate commands

* updated man to have warnings about strange values for zoom options

* Update help.raw

removed zoom-in/out

* removed zoom-in/out from options

* updated man/help entry to remove in/out zoom specification

* sanitize --zoom-rate in options parser; use a single variable for storing it

Co-authored-by: Daniel Friesel <derf@finalrewind.org>