Adding user filters
 V2 Ruby documents
Merge pull request #148 from thnkr/next-doc-release

Variables and mandatory filters first stab
 Changed navigation in tutorial Part 6 to include tutorial Part 7, Mandatory User Filters
Merge pull request #149 from thnkr/next-doc-release

Changed navigation in tutorial Part 6 to include tutorial Part 7, Mandatory User Filters
Added a first stab at user filters reference
 Corrected Additional Navigation Issues

 Adding user filters

 V2 Ruby documents

 Changed navigation in tutorial Part 6 to include tutorial Part 7, Mandatory User Filters
 Changed part 7 to link back to 6
 Changes to User Filters Guide