Add lib of commonly used asserts

- Add various assert methods commonly used by tests
- Groundwork for HTML Module Testing
- Upgrade ytestrunner and istanbul to be able to run custom YUI module
tests
- Add code coverage folders to .gitignore
Merge upstream changes
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Refactor based on upstream changes

Refactor to use new lib locations and split up common and Dom based
asserts
Rename files to be more consistent with what arrow uses

- Rename files
- Move config.json to ytestrunner.json, so usage is more obvious
- Add HTML Module test suite so it can do basic validation
Added support to Module Lib to run common node asserts

- Y.Test.isNode
- Y.Test.nodeTextEquals
- Y.Test.nodeCount
- Y.Test.nodeContains
- Y.Test.isImage
Add more Dom Assertions

Add
- Y.Test.nodeTextExists
- Y.Test.isAnchor
Merge pull request #43 from akshayp/master

Add Lib's to facilitate testing of modular markup components and expand Asserts library available for Arrow