Add cli argument to use different .topo or .params files

- Add cli arguments
- Refactor xmlparser functions
- Cleaned up and fixed some logging
- main.testDir is now set to the directory where the test file is
  located
- main.testsRoot is now set to the full path of TestON/tests/
    - Fixed usages accordingly

Change-Id: I2a0f0c3728b5732b242a2e860e6538a6f3b65166
diff --git a/TestON/tests/USECASE/USECASE_SdnipFunctionCluster/USECASE_SdnipFunctionCluster.py b/TestON/tests/USECASE/USECASE_SdnipFunctionCluster/USECASE_SdnipFunctionCluster.py
index 499df34..b984b1d 100644
--- a/TestON/tests/USECASE/USECASE_SdnipFunctionCluster/USECASE_SdnipFunctionCluster.py
+++ b/TestON/tests/USECASE/USECASE_SdnipFunctionCluster/USECASE_SdnipFunctionCluster.py
@@ -33,7 +33,7 @@
         """
         import imp
         main.case( "Setup the Mininet testbed" )
-        main.dependencyPath = main.testDir + \
+        main.dependencyPath = main.testsRoot + \
                               main.params[ 'DEPENDENCY' ][ 'path' ]
         main.topology = main.params[ 'DEPENDENCY' ][ 'topology' ]