Add basic functionality for lxplus.

Add basic functionality for lxplus. Add an additional local function
getting a string of excluded hosts. Fix a whitespace error in
__init__.py.
Add support for array jobs for lxplus and gridka.

Add support for array jobs for lxplus and gridka. Only implemented in
the respective _batchelor files. Implementation in the main batchelor
class is still missing.
Add function for excluding hosts on gridka.

Add function for excluding hosts on gridka.