Fixed the following:

- Added missing var statements for variable declarations
- Added TODO entries for code that needs to be used or further tested
- Removed unused variables
- Removed check of length > 0 as it's enought to check just item.length
  as a boolean
- Renamed scrolldown to scrollDown to keep a consitent style of method
  naming
- Removed extra jQuery wrapping for many objects and instead define it
  once and use it in the other places
- Use jQuery chaining for modifying connecting message in
  jarn.disconnect
- Define wrapped message in messageReceived from line 342 instead of
  expecting it to be received from the other messageReceived function