extract LambdaLifter from ExpressionParser
extract LiteralsTests from ExpressionParserTests
rename ExpressionParserTests -> FrontEndTests
move LambdaLifter to the compiler middle end

since Tortoise doesn't want it
relocate a comment
consistently say procdef not procDef

no strong preference either way, but best to be consistent
avoid gratuitous use of `print` in language tests

mainly for Tortoise's benefit, but also just generally a good thing
beef up testing of `foreach`
Merge pull request #573 from NetLogo/refactoring-lambda-lifting

extract LambdaLifter, move it from compiler front end to middle end