Access intermediary computation layers, testing with centre image only
* Added net init param 'force_single_input' for processing a single
  input image at a time (rather than the default batches of 10)
* Added net method 'getBlobByName' to get the output of intermediary
  computation blobs, and not just the final layer
* Added 'centre_only' option to the Matlab wrapper, and updated demo
  to use it
* Made compilation single core
* Updated Makefile.config and added matlab demo runner for titan