REF: Fitter docstrings and code updated to conform to numpydoc standards
FIX: path to static and math rendering

mathjax replaced with pngmath
[skip ci]
REM: Remove extraneous :math: tags

[skip ci]
Unnecessary math tags removed from docstrings to be replaced with unicode values as appropriate
REF: Updated docstrings to contain methods sections

[skip ci]
REF: Updated docstrings to include attribute and methods
UPD: Docstring cleanup

docstrings cleaned up to remove unnecessary :math: tags
FIX: mode missing from __init__ and problem with build_Q

Build_Q combined with load_file had problem due to pre-existing Q
FIX: Added file encoding
FIX: Addresses case where files in Data.__init__ is not a tuple
FIX: Form factor calculation bugfix (input dtypes)

Fixed an issue where using a combination of dtypes for the input hkl tuple would result in ValueErrors.

Changed the method of checking dtypes and calculating the initial zero value for the loop over each atom.
Merge branch 'structure-factor-bugfix' into develop
Travis-CI script update

Switched over to Miniconda for compatibility
Merge branch 'develop'