Be sure to include intersense include directories.
Intersense isn't GPL-compatible.
Fix python 3 binding issue found by a visual studio warning.
Update the Intersense SDK finder to handle Windows (and Mac).

Supports looking in INTERSENSE_ROOT_DIR as the
unzipped SDK directory from InterSense.

Designed to work with the three versions I could get:
4.2381, 4.237, and 4.2110. Tested to compile on Windows with VS2012.