Added -i option to create a configuration file interactively

- When PMAP in invoked as python PMAP.py -i configurationFile.config,
the user is asked to input the minimum parameters needed to run the
pipeline successfully.

- Also, calclScale is now an independent function in pdrLib.

- defaultOptions.dat has been modified and now it does not use inline
comments. The changes should be backwards-compatible.
Merge branch 'development' of https://github.com/astroPDR/PMAP into development