Cleanup and check for nil

Also add more testing

fix broken groups

Merge pull request #59 from desdic/fix/groups

fix: make run groups work again

fix: add hook to file extension

Merge pull request #58 from desdic/fix/hook

fix: add hook to file extension

doc: Improve documentation

Merge pull request #57 from desdic/fix/documentation

docs: Improve documentation

feature(file): Added a file extension

Merge pull request #56 from desdic/feature/file

feature(file): Added a file extension

fix/missing returns

Merge pull request #55 from desdic/fix/returns

Add missing returns

remove last_first and add GreyjoyRunLast

Also remove deprecated terminal usage

fix(fzf): bufname and filetype was wrong using fzf

Merge pull request #53 from desdic/fix/buf

fix(fzf): bufname and filetype was wrong using fzf

refactor term

term now uses 20% per default to display runner (old behaviour with hight is deprecated but still works)

feat: Move terminals to separate function

• Give deprecation warning on old Settings
• Add support/example for builtin term
• Fix spelling in default configuration