fix: limit comment edits (js) to 3000 characters
fix: limit comment edits (js) to 3000 characters

If a user who is using js tries to edit a comment
to include more than 3000 characters, the ajax
request handler will not allow it.

Resolves: #12

tstillwell2k17/GAE-BLOGAPP-MULTI_USER-DEMO,tstillwell2k17/GAE-BLOGAPP-MULTI_USER-DEMO,tstillwell2k17/GAE-BLOGAPP-MULTI_USER-DEMO