Created slurm launcher for workflow plugins

This hasn't been well tested but it should work without too many issues. Of particular note are the environment variables that we're referencing. Those commands have the capability to fail with no error and need to be watched closely.
Fixed misnamed variable causing crash.

_sbatch_args was incorrectly called _slurm_args in one of the if
statements in slurm.py causing a crash. Added in a load .slurm to
__init__ as development env had plugins in PYTHONPATH. Moved slurm
plugin base to base.py instead of slurm.py
Added support for sbatch args to slurm module.
Added mandatory args for SLURM, fixed regex for batch job number

Added in several defaults for mandatory arguments to sbatch. Also the
regex that finds the job number was malformed and was returning 'None'
for all batch jobs. That's been fixed and is now returning jobs
correctly.
Merge branch 'master' of https://github.com/ChadCumba/nipype
Fixed a typecasting bug on some systems

strict python interp was killing o.find(<int>). typecasted to str.
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.
docs and changelog
Merge branch 'pr/629'

Conflicts:
	CHANGES
	nipype/workflows/fmri/fsl/preprocess.py