Updated installation instructions to reflect new Pip install ability.
Brought Getting Started instructions up-to-date.
Simplified `Installing...' section, as per newly cleaned up `setup.py' (i.e. - v0.5).
Updated link to Windows installer.
Added "Contributing..." section.
Added link to "Introduction" page, in "Adventuring Further" section of "Getting Started".
Initial revision of "Getting Started" page.