Kibitzr

Fixed
- Fixed xpath selector transform.

Fixed
- Fixed interruption exit code (1).

Fixed
- Exit(2) when receiving SIGTERM/SIGINT.

Fixed
- Exit(1) Kibitzr when Firefox goes funny business.

Changed
- Firefox fetcher: Implicitly wait 2 seconds for selects.
- Firefox fetcher: Resize window before each fetch.
Fixed
- bash transform: Skip execution for empty content.

Added
- Changes style "new" - show only current content if it changed.
Fixed
- text filter in Jinja templates.
- Adapted list of requirements for Windows.