add to_string fun for MultipartReq; tableFeaturesReq; TableFeature; TableFeatureProp; FlowReq
change the type multipartReq
add of to_string function for the module multipartReq and its dependencies
Create an oxmHeader function in module Oxm
change of TableFeatureProp type
change of MultipartReq type
Add test & correction for table feature prop
fix line break
Module tableafeatureProp:
- move of sizeof fun
- add padding
- parse only the content (not the pad)

Module tableFeature:
- offset correction
- remove of length
- add roundtrip testing
add test for TableFeatureReq
add flowRequest roundtrip test
correct test for tablefeatures (non empty list)
add multipartReq test
merging to add new test (multipartReq and dep)