deleted Test*.scala. Now we have enough examples in the examples folder to describe how funcheck works

Instead of passing a random position to method Fresh.newName, now passing object NoPosition when I have no idea of what is the right position.

renamed file so that ant doesn't try to compile it (the example should be updated so that it uses ScalaPure, the Scala functional subset that we use for FunCheck).

Delete duplicated examples. These are somewhat overlapping with the ones defined in tests/plugin/ folder

forAll are now correctly translated also in their returning type, before it was Unit (wrong), now it is always a boolean.

Specs implication is now working correctly. Arguments needed to be evaluated lazily. Now all properties in LeftistHeap can be checked correctly.

Fixed bug in arbitrary function used to link Scala AST Type element to its Arbitrary function for generating arbitrary object of the data Type.

MapReducer need to use multisets for abstracting away order in lists. Now forAll properties does not fails anymore.