Added https://github.com/afterdesign/jshintify to plugins list

jshintify has some options that are not present in other jshint plugins:
- set path to jshintrc file
- set what is showing in status bar (options called ```error_messages_show_count``` and ```error_messages_show_first```)
- option to show/hide dot in lines with errors
- option to show/hide outline for lines with errors 
- option to filter files based on extension
- lint file on open
- additional option to show debug messages for easier issue reporting
- cool animation in statusbar (borrowed from pylint plugin)