Image array handling and drawing utility

Utility functions to quickly render image array returned by
`ipzCaptureWindow2` (Not yet complete)
intermediate commit for timeout function

Intermediate changes added for incorporating timeout functions
intermediate commit for timeout function
Data item set completeness test code

Simple utility program to test if PyZDDE contains all the data items
defined by ZEMAX.
Image handling utility for notebooks complete
Updated to revision 0.7.2

Main changes incorporated
1. Usage of `timeout` function for global and few individual functions
now possible.
2. DDE handling moved from PyWin32 to PyZDDE's DDE code (PyWin32 can
still be used by turning appropriate boolean flag)
3. Helper functions for better image array handling in IPython notebook.
commiting to merge changes
commit to merge changes
Merge pull request #17 from indranilsinharoy/working

Working