Add sanitizing function for mapping file

This function is called from the main script interface and it will
replace all of the ' or " characters with an escaped version that will
not affect javascript.

Test module was updated accordingly.

Closes #52
Move sanitizing to preprocess_mapping_file
Add changelog file

General features were added into this file.

Fixes #41
Divide ChangeLog notes in features & improvements
Merge pull request #55 from ElDeveloper/issue_41

Add changelog file
Remove ' and " instead of escaping
Merge pull request #53 from ElDeveloper/issue_52

Add sanitizing function for mapping file  -- fixes issue 52
Merge branch 'master' of git://github.com/qiime/emperor into issue_12
Add visibility and color GUI elements for biplots

The color of the biplots on screen can now be changed to any color.
The biplots can now be turned-off.