new class DefaultMocksInstrumentationTestCase to initiatlize XMLRPC and Rest Factories with default test factories
rethrows IOException and XmlPullParserException in our XMLRPCClient Mock
add a few tests to check for #1189 - fix #1197
Merge pull request #1431 from wordpress-mobile/issue/1197-xmlrpc-tests

fix #1197 xmlrpc tests