Added 'Fork me on github' banner

Signed-off-by: Thameera Senanayaka <thameera123@gmail.com>
Introduced saving options in local storage

Currently, WPM, delta and chunk size are saved.
Ability to revert to the default settings was given as well.

Signed-off-by: Thameera Senanayaka <thameera123@gmail.com>