all single quotes to double quotes in code
update to gitignore for Tex and OSX
Merge pull request #124 from ehsteve/code_updates

Simple code updates and gitignore
Make reference list consistent and in one bib file.

Closes sunpy.sunpy-0.4-paper/#121
Add Python package references to introduction.

Closes sunpy/sunpy-0.4-paper#119
Merge pull request #125 from Cadair/references

References
small changes to address #122
fix for issue #111
Fix for issue #113
Merge pull request #128 from ehsteve/master

Various Mixed up Fixes to text