Move LispVal type check functions to Neautrino.Internal.Type
Add pushVar, popVar functions in Neautrino.Env
Bind alias parameters of closure to arguments.
Refactoring
Add 'caaaar' to 'cddddr' functions
Import 'cond', 'case' macro from chibi-scheme
Rename Neautrino.TestUtil to Neautrino.HspecHelper