Cylon.py

- Added following keywords.

feature
Then the [...] is enabled
Then the [...] is disabled

- Fixed to wait and check url after open page.

- Fixed code to check when enters, clicks and selects fail.
- Fixed code to check selected text on select.

- Fixed following keywords to wait for expected state (timeout 8 seconds).

feature
Then the [...] exists
Then the [...] does not exist
Then the [...] is visible
Then the [...] is invisible

- Fixed `IndexError: string index out of range` when run without `site=<site>` option.
- Fixed cylon command to has return code when test failed.

NOTE: Need to run `cylon update project` command.

- Fixed `AttributeError: 'Configuration' object has no attribute 'site'`

NOTE: Need to run `cylon update project` command.