Updated install docs with install from github

Almost the same as is in the README.
Fixed typo in the README install section.

Fixes #14
Merge pull request #125 from leouieda/install-development

Updated install docs with install from github
Moved README to Markdown
Spaces between the link separations
Put the banner on the README title
setup.py should load README.md not .rst
Merge pull request #130 from leouieda/readme

Added more links and the banner image to README
Updated citation file
Updated links to github repo

Need to point to the Org repo, not leouieda
Merge branch 'master' into tesseroid-kernels