Remove AdtPlugin dependency from AttrsXmlParser.

Remove AdtPlugin dependency from AttrsXmlParser.

The AdtPluin was used just for logging. Instead the
AttrsXmlParser takes an ILogger (AdtPlug implements
ILogger and can be used directly in unit tests too).

For unit tests there is a new StdSdkLog convenience
class that prints to stdout/stderr (formerly MockStdLogger
from the Sdk Manager was doing that.)

Change-Id: I658af61d04efb19ad6e3bf9c0bf471452372885a