Preliminary update to support CM v3.01 and later

In v3.01 addons were moved into a dedicated directory. The first commit supports all versions of CodeMirror from v2.0 to v3.12.

The second commit is red with tabs. Every editor file has been replaced with a red file except for editor-cm.html (previous version renamed to classic). server.py has a generic minor change to revert to allowing spaces in file and folder names. The editor files have not yet been removed so for now it's still possible to switch between CM and Ace. red with tabs requires CM v3.1 or later.

Fixed Reload pytronics and other minor improvements

Replaced button/tab bar table with css