DOC: Added Ni known d spacing
DOC: added CeO2 (hkl) values (angles) values and wavelength
DOC: added Alumina(Al2O3) (hkl) values and (twotheata) values for XPD
DOC: modified nsls2/constant.py
Merge pull request #169 from sameera2004/add_constants

add_constants : Calibration Standards for Powder diffraction data
init of adding voigt and pvoigt functions
add two functions
add tests
correction
more corrections
Merge pull request #170 from licode/pvoigt_function

ENH : Voigt/Pvoigt function
BUG: Fixed docstring bug in calibration that prevented autowrap
Merge pull request #171 from giltis/calib_bug

DOC : Fixed docstring bug in calibration that prevented autowrap
WIP: modified:   nsls2/recip.py to add q values for each pixel from hkl values
ENH: modified:   nsls2/recip.py
ENH:  modified:   nsls2/recip.py
DOC: added documention for HKL to q
ENH: changes according to comments
ENH: nsls2/recip.py
ENH: changed according to comments