MNT: Removed reinvented wheels in favor of lmfit

Also aggressively renamed functions
DOC: Find the indices and number of pixels for rectangle shapes
open this branch due to conflicts in the previus branch
TST: added a ROI which goes out of bounds
simplified the for loop
Merge pull request #178 from sameera2004/q_rectangles

ENH : Find the indices and number of pixels for rectangle shapes
WIP: Converts radius from the calibrated center to twotheta
TST: added a test to radius_to_twoteta
TST: modified the tests to change it to assert_array_almost_equal
STY: changed for PEP8
DOC: added a prose description
Merge pull request #182 from sameera2004/radius_to_2theta

ENH : Radius to two_theta
Merge pull request #176 from ericdill/fit

Removed functions that already exist in lmfit
ENH/TST : add decorator to skip tests
Merge pull request #185 from tacaswell/skip_decorator

ENH/TST : add decorator to skip tests