adding verify_configuration_flag func
updating doc string
testutils: remove out_port arg from verify_flow_stats

This was never used and caused problems with OF 1.3.
add flow_mod testsuite

Just one test for now, which checks overwrite behavior.
Merge into master from pull request #122:
flow overwrite testcase (https://github.com/floodlight/oftest/pull/122)
Merge into master from pull request #107:
Verifiy configuration flag (https://github.com/floodlight/oftest/pull/107)
Merge into master from pull request #125:
update pyloxi to floodlight/loxigen-artifacts@82ba9ace14a6a71383b79e62cc... (https://github.com/floodlight/oftest/pull/125)
update pyloxi to floodlight/loxigen-artifacts@60b6e39c8a5dddade0ad293da512d9dd57ed2f98