Update README.md

Merge pull request #5 from gkjohnson/dev/code-mirror

Add image, fix a few bugs in the clients

Update package.json

Update README.md

Punctuation

Merge pull request #4 from gkjohnson/dev/code-mirror

Update README.md

Provide code-mirror example

Package.json cleanup

Add code-mirror package

Add proper cursors to shared text selection markers

Update README.md

Merge branch 'master' of https://github.com/gkjohnson/collaborative-code-editor

Small cleanup