BUGFIX: Fix not being able to save when there is an empty file in create screen.

Fixes #28
BUGFIX: Files that do not exist in github do not send a patch request upon deletion.

Fixes #79
FIX (drag & drop): drag area disappears on drag cancel

- fixes drag area getting stuck with drag & drop zone activated after cancelling a drag & drop operation

Closes #84
FIX (deleting a file): local copies of files now properly delete when not yet saved to GitHub
DOCS (readme): create COMMIT_GUIDELINES.md

- create COMMIT_GUIDELINES.md
FEATURE (single gist): present fork info if gist is forked

- Show fork info for forked gists, info like src URL, creator etc.
Merge branch 'feature/show-forks-info'
FEATURE (share gist): add auto-completion to share gist

- add auto-completion of GitHub followers to share gist
- if share addressee is not a follower, his username will be added to the list

Closes #83
INFO: auto-completion pulls list of followers following You on GitHub and keeps share addressee which are not a follower