Fix the build and tidy up

This PR fixes the red build we've got on the CI and tidies up some stuff:

 * Removes bugsense. It doesn't make much sense to have it in the demo project and also we were using a really old version. One of the reasons why the build failed on the CI was using the wrong plugin id for Bugsense (now Splunk)
 * Another fix is I added the missing `<application />` tag in the pxfetcher module.
 * I've updated the build tools to use the latest (improves build performance)
 * Removes unnecessary AndroidManifest file in the core module, not sure why this was here lol
 * Small lint fixes in the demo project

PROOF:
![screen shot 2014-10-03 at 11 51 09](https://cloud.githubusercontent.com/assets/1626673/4504797/3d04929c-4aeb-11e4-8d81-11fbaae711c8.png)

it's local now, it was a field before but there was no need
Here @blundell : https://github.com/novoda/ImageLoader/pull/174/files#diff-b640b9b7866d23f09ed0571d454c7d4cL24