changed UI to show a unified script list (installed + repository) and a
separate detail section

(#26 - cherry picked from commit 8f4935ce55ab8a8d6b980fe32dff98843225f031)
fixed: adding a listed script by entering the number now updates the UI properly

(#26 - cherry picked from commit 38b756669674b794e652f8df45fa2bab0d8ac39f)
fixed: removed hardcoded fetching of local scripts

(Closes #26 - cherry picked from commit 48f620f45a38a1e8f8c9af69dd1746efba3d7d68)
whitespace and other minor tweaks
details pane style changes, listing reason for script being displayed in
the list, and minor tweaks
Minor details pane formatting to support 'how to install' text.