Merge pull request #1 from mperrin/master

First steps
Merge pull request #2 from mperrin/master

Lots of updates: class interface, plotting tools, documentation, iPython notebook
Merge pull request #3 from mperrin/master

Progress towards chi^2 fitting in Python and more
Added image and SED chisqrd calculators and the likelihood estimation function.
Merge pull request #4 from swolff9/swolffbranch

Added image and SED chisqrd calculators and the likelihood estimation fu...
resolve conflict with Schuyler's edits
resolve conflict with Schuyler's edits