Added sublime-open-path

Plugin for open project/file path in OS's browser, and for providing this api for external plugins. See https://github.com/Shagabutdinov/sublime-open-path for more description.
Update repositories.json

Slash removed from "Open project/file path by shortcut" as it is used as the name of the directory that is created when package is installed
Merge pull request #893 from Shagabutdinov/master

# By Shagabutdinov
# Via Shagabutdinov
* Shagabutdinov/master:
  Update repositories.json
  Added sublime-open-path

Conflicts:
	repositories.json