Add documentation in HTML format

A new folder has been added to the repository named doc, this folder
contains the documentation for the project as it is so far.

The main contents are:
    - Introduction
    - Description
    - Tutorial
    - Installation Tutorial
    - Links to the usage examples (these should be changed once #96 is
      fixed).

Fixes #107
Add Fork me on GitHub ribbon
Add note about documentation on ChangeLog.md
Merge branch 'master' of git://github.com/qiime/emperor into issue_107

Conflicts:
	ChangeLog.md
Change links to point to emperor.colorado.edu
Merge branch 'master' of git://github.com/qiime/emperor into issue_107

Conflicts:
	ChangeLog.md
Remove PSD files from the img folder
Update index.html and description_index.html

These files now display images with the latest version of Emperor i. e.
post view_menu_2 merge.

It also features a couple corrections that @antgonza made to the main
text.
Update files to the latest version of Emperor
Update tutorial images and text

These updates were required based on the latest changes that have
ocurred in the repository.
Add @antgonza's suggestions to the text
Change sentence to remove a grammar mistake
Merge branch 'master' of git://github.com/qiime/emperor into issue_107

Conflicts:
	ChangeLog.md
Merge pull request #116 from ElDeveloper/issue_107

Add documentation in HTML format