Added a missing CPDate.j import in CPExpression_function that was causing an 'unknown variable CPDate' error in deploy builds.
Added documentation for +expressionForSubquery:...
Added licence headers with credits.
"($)path.($)variable"
"SUBQUERY(collection, $x,$x = 2)"
"sum:(arg1, ...)"
"FUNCTION(target, selector, arg1, ...)
"object[expression]"
"set UNION|INTERSECT|MINUS otherset"
Fixed a bug where CPExpression_set was evaluating to an expression instead of a set.
Replaced parsing exceptions with a generic function indicating where it failed.