Added Age related operators to the clinical expression schema.
Example syntax updates.
Support for uncertainties, refactor date and interval operators to use uncertainties, support integer intervals
Changed And, Or, Union, and Intersect types in ELM to be Binary, rather than Unary expressions. Ballot comments #127 and #183.
Fix age example in coffeescript execution framework
Add CQL execution support for: 3-valued xor, not, union (lists), intersect (lists), distinct, null.
Set explicit tools version for JaCoCo to fix a build issue w/ Java 8.
Uncertainty scratch pad musings.
Updated the ChlamydiaScreening_ELM example based on the latest version of the ELM.
Fixed some schema validation issues in the translated ELM example.
Fixed namespacing issues with the ELM annotations output so that the resulting ELM XML is schema valid.
Added all/distinct specifier to return clause.
Allowed for multiple expressions to be returned in a return clause.
Fixed a code warning that was failing the build.
More refinements to the return clause based on implementation feedback.
Add new QueryDefineRef in ELM along with support for it in the translator
Merge pull request #2 from cqframework/query_define_ref

Add new QueryDefineRef in ELM along with support for it in the translator
Fixed unit test that broke as a result of my commit before the QueryDefineRef merge.
updating Context class to have notion of parent so contexts can be chained while maintaing scope.  Added mutlisource query implementation
fixing a few stylistic issues and implementing ExpressDef caching on root patient context
 adding expressions for Tuple, QueryDefineRef, AliasRef and Property.  Reworked Query exectuion to return tuple from MultiSource queries by default along with a few bug fixes