data_source now can grab E_g from ENDF File 3
implemented _load_reaction & tests
implemented _load_reaction & tests
cleaned up list comprehension of numpts
changed ENDF reader example for fun and profit
Merge remote-tracking branch 'upstream/staging' into staging
First pass at integrating energy ranges
Indexing-based integration. Lin-log, log-lin, and log-log to come soon.
Test cases for linear and histogram
Moved integrators into top-level; linlin and histogram normalize now
Added docs for interpolation math, implemented lin-log
Trying to fix discontinuities.

Using masked arrays to ignore NaNs from 0-width sections,
which are generated by discontinuities. When summed, masked
constants are treated as 0 in iPython notebook. However
sum() spits out "masked" when actually tested...
Merge remote-tracking branch 'upstream/staging' into staging
Merge remote-tracking branch 'upstream/staging' into staging
Fixed summing, added more integrations

Fixed summing masked arrays and added integration code and math
documentation for loglin interpolation. No tests for loglin or
loglog yet.
Merge remote-tracking branch 'upstream/staging' into staging
First stab at Special ENDF Interpolation
Wrote tests for interpolation schemes 1-5
Implemented discretize in data_source.py for ENDF.
Changed xs_gs to dst_sigma to fit in better.