Format on save

[piuccio]

This closes #2

It's potentially breaking #10 :smile:

@leobalter do you happen to have some time to check this PR on Mac? Would be amazing.

[leobalter]

ST2 on Mac:

• [x] Format on save
• [x] User settings over defaul settings
• [x] nodejs path
• [x] Custom preset
• [x] It's not breaking with special characters (#10)

ST3 on Mac:

• [x] Format on save
• [x] User settings over defaul settings
• [x] nodejs path
• [x] Custom preset
• [x] It's not breaking with special characters (#10)

All done

[leobalter]

I also sent #25 as I missed this on the settings as an example.