Fix date tests

Fixes the test case to pass the tests in your own environment. Cause is
probably the difference of time zone, the tests should pass independently
of the environment.
Fix expected value
Update tests to avoid API testing with using API
Remove unuse variable
Improved tests to the detection of AM and PM that it does not depend on the API
Add ability to filter log messages by threshold

This allows configuration of a minimum log level. Log messages greater than
or equal to the specific log level will be included in the log output,
others will be discarded.
Fix #583. Allow upper and lowercase `to` values for `convert()`. Also return original value if an invalid `to` value is provided.
Update charts user guide to indicate the need for the charts-legend module to create legends. Fix #2533219
Merge branch 'dev-master' of github.com:yui/yui3 into gh-583
Build Color.
Fix %Z format tests
Merge pull request #520 from okuryu/fix-date-tests

date: Fix unit tests
Merge branch 'yui-log-minlevel' of git://github.com/andrewnicols/yui3 into andrewnicols-yui-log-minlevel
Seed and Loader build
Seed and Loader build after dev-master merge