Convert\VarSetType for always return type expected (eg string will be string)
or Convert\VarSetTypeNull to return string or null on failure
The return value for failure if not matching type can be set for both, but
only for Convert\VarSetTypeNull the return value can be set to null.
Smarty extended class is now included in checks and is fixed.
Add the lib/ folder to the composer.json autoloader block so we can use
the composer autoloader and not the one from CoreLibs
Added an autoloader load test backend file
