Basic module extended type checking & relative base URLs for createRe…

…stfulJsonClient

// implemented explicit type checkers for everything isA() supports (except null und undefined, which can be checked with ===) to improve readability and safe on uncompressable strings in source (+unit-tests)
// replace occurrences of isA() in source with new explicit type checkers
// added "htmlcollection" as newly available type for isA() and getType()
// added possibility to set empty or relative baseUrl for createRestfulJsonClient, which get auto-expanded with window.location.origin
// upped version to 0.1.6-beta