[app] Update progress sheet button title once done.
[app] Interrupt task when clicking ‘Cancel’.
[app] Change working directory to that which contains the Podfile.
[app] Bind progress output view to internal storage.
[app] Do not make output view editable.
[app] Set LANG env variable.
[app] Add podspec for ANSIHelper.

From https://github.com/ali-rantakari/ANSIEscapeHelper
[app] Install ANSIEscapeHelper.
[app] Colourise command output.