parpost.py and aep_del.py: standalone parallel post-processing

parpost.py: a utility script to perform parallel logfile analysis, calculate statistics and envelopes. Intends to replaces the post-processing capabilities of dlctemplate.py. Contrary to dlctemplate.py this script can operate on any random set of result files and does not require anything else.

aep_del.py: calculate AEP and DEL, modular version. dlctemplate.py has the same capability but the AEP/DEL calculation is buried deep somewhere in prepost.Simulations.AEP and which neither transparent nor easily usable in any other context outside the workflow of dlctemplate.py.

Fixes #111 (closed).