Tag v0.6 for release

[kadamwhite]

V2 parity is not complete, but in light of API V2 beta 11 and changes that have been made to support posts and taxonomy collections, we have enough for a release!

PRs included:

• Added support for array filters #117 - Added support for array filters
• Bump versions for all NPM dependencies (fixes #119) #120 - Bump versions for all NPM dependencies (fixes Upgrade route-parser to latest version #119)
• Add integration tests for post creation & updating #123 - Add integration tests for post creation & updating
• Test on Node.js v0.12.x, v4.x, and v5.x #125 - Test on Node.js v0.12.x, v4.x, and v5.x
• Support v2 Taxonomy Routes #126 - Support v2 Taxonomy Routes
• Move param() handling and renderQuery method to WPRequest #128 - Move param() handling and renderQuery method to WPRequest
• set _paging property on result of all paged requests #129 - set _paging property on result of all paged requests
• Add forpost method to tax collections #131 - Add forpost method to tax collections
• Alter .slug() collection filter method to use new ?slug= parameter #132 - Alter .slug() collection filter method to use new ?slug= parameter