@abose I have updated this pull request to follow the same format as adobe/brackets-shell#545 .

For the files which have only a single year mentioned in their License header (like https://github.com/adobe/brackets/blob/master/src/LiveDevelopment/Agents/ConsoleAgent.js ) should I make their year format as Mentioned Year - present ?

Also should I do a single commit with these updates or should I break them up by years mentioned in them (mainly asking how to break them up in stages)

Mentioned Year - present would be fine in those cases.
It would be good to do all in a single PR, but with different commits- maybe folder wise in the source tree.
Also, note that 3'rd party code licenses may not be altered. Only change **ADOBE licenses** to the new format.

@abose Updated all the Adobe Systems Incorporated. licenses and committed them folder wise.

Verified all licences.
Merging as confirmed with @ryanstewart
Thanks @pra85 for making this change.