Split python and javascript files

Split the single acj.py file into several new files to reflect logical groups. This also changed the directory structure.
The application is now started by running runacj.py in the root directory. All other files moved up one level to the new acj directory.

Also split acj.js into 3 new files, acj-config.js, acj-controller.js and acj-directives.js.
Added styles for mobile devices
Limit answer length

Added an option to limit the length of  answers and comments for a question.
As mentioned in Issue #37, there are certain difficulties with limiting the length here, so the validation is only done in Javascript.
Minor changes for mobile displays
Merge branch 'develop'