Merge pull request #1 from dmbates/master

Add a requirement of the PyPlot package (which, in turn, requires PyCall)
Merge pull request #5 from dmbates/master

Change example to use Pkg.dir
Implemented noweb reader in Julia

Causes changes to chunk option formatting. Updated sample accordingly.
Updated Readme
Made rcParams const
Fixed readme formatting
Readme typo
Exception handling for invalid chunk options
Added .gitignore