Organizational changes per Satrajit's requests.

Removed base.py slurm base class and instead rolled it all into
slurm.py SLURMPlugin class, which now inherits
SGELikeBatchManagerBase. Also changed the default queue time to 1 hour
as users did not like default 48 hour queuing.
Corrects output for slurm outfiles.

Environment variables can override this, but we are now storing the
slurm.out files in the batch directory with the other batchfiles.
This commit also removes the hardcoded link to the bbr file in 
$FSLDIR/etc/ and replaces it with a relative path starting from 
$FSLDIR.