Version 0.1.5 Fixes

Changes for version parallel bilby 1

• Remove redundant pool.wait [@conrad.chan]
• Add Max Iterations fix [@conrad.chan]
• Add schwimmbad_fast.py allowing MPI worker tasks workers to spawn at the start and persist until the end (no benefit to killing them early) [@conrad.chan]
• Fix trigger time parser to read strings [@colm.talbot]
• Remove mem per cpu default [@maite.mateu-lucena]
• Add nestcheck file option [@maite.mateu-lucena]
• Add constructing sky frame parameters [@colm.talbot]
• Change MPI isend --> send (to allow master task to finish sending messages to workers)[@conrad.chan]
• Disable the flag messages when timing is off [@conrad.chan]