_eselect: don't duplicate common values
_eselect: function spacing consistency
_eselect: fix minor spelling and indentation issues
_eselect: remove unused variable and fix indentation
_eselect: use --brief option to simplify value parsing
_eselect: escape colons in profile list

Zsh uses colons in completion values to separate field names and values
so the profiles with unescaped colons don't show up for completion.
_eselect: update opengl options