nanshe/nanshe_learner.py: Attempts to import drmaa if installed. If not installed, a warning is emitted by the logger.
nanshe/nanshe_learner.py: Only tries to import drmaa if it is intended to be use. Errors if it is missing or libdrmaa.so is missing.
nanshe/nanshe_learner.py: Attempt at adapting job pool for drmaa.