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
IMPROVE (single gist): revision of present fork info if gist is forked

- revision of present fork info if gist is forked.
Merge branch 'master' into bug/bigGistFiles
FIX-PROPOSAL (gist API): gisto fail to handle files >1MB PROPOSAL

- add delay to bigger files so they will be able to load

Fixes #85