fix JSON stringify to escape special characters

When converting from non string types the converted string was not escaped
WinRegistryKey::getInt64 failed to read QWORD type from the windows registry.
BINARY data type support for WinRegistryKey
unit tests and changes according to comments
Merge pull request #533 from rafzi/develop

fix JSON stringify to escape special characters
Merge pull request #537 from InnovaCo/winreg-binary-support-and-int64-fix

WinRegistryKey::getInt64 failed to read QWORD type from the windows regi...
added Var::isBoolean() and fixed JSON stringifier
improved Crypto tests