Added two buttons to change the font size at the debug window and improve help command autocomplete

[aitorp6]

Hi.

I have added two buttons on the debug window to change the font size, to make it bigger or smaller. Other wallets as BTC or Dash have this features implemented. The main code has been taken from there and has been modified to work in our wallet.

See the attached images to understand this:

I have tested it only on Linux, I think that it should be a good idea to test it on the other OS.

[aitorp6]

Hi

I have added a better autocomplete functionality. Now "help + command" is too autocompleted.

Even is the list is small, I have added the code to sort it alphabetically , this would improve the speed on generating the list.

[deeponion]

thx