Refs #8373 Indexed curly brances in format statements

This is needed for python 2.6

modified: StretchedExpFTTest.py
Refs #8373 unittest.TestCase.assertLess not implemented in python 2.6

Changed to assertTrue

modified:   StretchedExpFTTest.py
Refs #8373 Do not perform unit test until scipy in MAC resolved

It turns out scipy is not installed for the MAC :(
Move scipy imports so that they don't happen on startup.

There seems to be an issue with loading scipy while mantid is
imported in vanilla python. Move the import so that it happens later.
Refs #8373