Add character count

[vankasteelj]

• Add char count (spaces included) on hover
• Update description in readme

Code:

• Lint (3 warnings fixed)
• Use singlequotes
• Remove unneccessary trailing underscore in _handleWordCount

[cfjedimaster]

You won't believe this - but I just had a work request for some writing that - for the first time - included a character limit, not word. This is perfect. Thank you.

[vankasteelj]

This bothered me too much too :D It was the only reason I still opened Word for most of my text files