Cursor leakage due to cancellation signal

If a query call was cancelled, the cursor adaptor might leak. The
adaptor is now closed if any exception is thrown during query.

Change-Id: Ic4c2edeaf2fcef56b4ef59484a36d3233aa12dbc
XmlUtils#readThisMapXml should handle null keys.

Both readThisValueXml & writeThisValueXml have been
implemented to handle values with "null" names.

Change readThisMapXml to allow such names as well, and
map them to the null key in the resulting HashMap.
readThisListXml and readThisSetXml already support
null names.

bug: https://code.google.com/p/android/issues/detail?id=63463

Change-Id: I1c93976656e45e7733113eb67d29b6bad5d25f1f
QS: GPS Tile tweaked

Thanks to slimroms