[ADD & EDIT]

- edit auto layout to each view controller (change background colour,
apply design of .xib files on storyboard)
- add status colours (label) to ‘service testing’ tabs
- delete progress bar but using activity indicator instead
- add UIColor to fulfil status labels
- add UITimer to set time interval in order to display colour after 1s
- add function to support randomly display colours by clicking on
’start’ button