[+]: add more "is*" methods (isAscii, isBinary, isBom, isBinary, isUrl, isUtf8, isUtf16, isUtf32) from Portable-UTF8
[+]: add more "is*" methods (isAscii, isBinary, isBom, isBinary, isUrl, isUtf8, isUtf16, isUtf32) from Portable-UTF8

TODO: add some tests

issue #30

voku/Stringy