complete bucket module (to_string, parse)

groupType : add to_string and parse
and correct OFPGC -> OFPGT

add groupDesc module
add groupFeatures module
add MeterStats module
add meterfeaturesStats and add new types to multipartReply
complete groupMod module
change TableFeaturesRequest to TableFeature
add TableFeatureReply
complete meterBand module
move MeterFlags to a separate module
complete meterConfig module
add unitary test for missing multipartReply
merge from master
add missing messags
issue #131, MultipartMessages export its type
move function of GroupFeatures in submodule
move function of MeterFeaturesStats in submodule
move function of MeterStats in submodule
correct padding for bucket
change GroupDesc to basic type

add rountrip test for bucket and groupdesc
change MeterStats to basic type
change to basic type for:
QueueStats
PortStats
TableStats
FlowStats
GroupStats
MeterConfig

move flags function to submodule ine flowmod

remove of PortsDescriptionReply (duplicate)

add GroupStatsReply rountrip test
Merge remote-tracking branch 'upstream/master' into multipartReply

Conflicts:
	lib/OpenFlow0x04.ml
Merge pull request #130 from fugitifduck/multipartReply

Multipart reply