First success with calling IDL from python

* Used subprocess.Popen command to achieve this.

* Biggest issues were:

  - Windows does not have a good bash shell so a lot of scripts fail.
  - Subtle syntax difference between examples found online and what works
    for IDL 8.1 on Windows 8.  Specifically, it matters where I use single
    or double quotes.
  - Had to put in the proper ENV variable so that idl can be called
    properly.
Python can use IDL prompt to print date of specific shot
Extracted date successfully from foldername.pro
Cleaned up idl_support and implemented get_shot_date

* Cleaned up the formatting found within idl_support.py.
* Converted the script/static version of calling IDL's foldername pro
  to a dynamic version.
* Call get_shot_date(shotnum) to have it return the date corresponding to
  the shot.