Added stack to runtime.
Renambed LCPP_(RUNTIME|VOID|NIL|...) to LCPP_(pRuntime|pVoid|pNil|...)
LCPP_TEST => LCPP_TestCase,
LCPP_TEST_GROUP => LCPP_TestGroup.
Runtime now has a Statistics struct, which currently keeps track of the number of initializations and shutdowns of LispRuntime.
Added unit test that checks that the runtime is always properly reset for every unit test.
Implemented typeCheck and number::integerValue.
Unit test for number::floatValue