Add extension support for UO-1-ID packet

Scheduled for 2.0.0.

Support added in main branch. See http://bazaar.launchpad.net/~didier-barvaux/rohc/main/revision/788

* update the compressor function to code extensions for UO-1-ID,
* update the decompressor function to parse extensions for UO-1-ID,
* update the compressor algorithm that decides which packet type is
   the better one to make use of the UO-1-ID extensions,
    * the RTP Marker bit can now be updated by UO-1-ID with extension 3,
    * more than 1 IPv4 header with non-random IP-ID bits can now be
       transmitted with extension 3,
* always put the IP-ID bits of the innermost IPv4 header with non-random
   IP-ID in base UO-1-ID header,
* there is no reparse need for UO-1-ID extension 3 as there are for
   UOR-2* extension 3, but a check for changing RND bits was added,
* update the rtp_uor2_disambiguation test for UO-1-ID (renamed
   rtp_uo_disambiguation in consequence),
* update the output PCAP files of the non-regression test in
   consequence: some more bits are saved :)