[PATCHSET] Extended matches and basic classifier

[Thomas Graf <tgraf@xxxxxxx>]

This patchset adds the ematch API, the ematches cmp, nbyte, u32, meta,
and the basic classifier. It doesn't touch any existing code.

The following changes were made since the last review:
 - various typo and bug fixes
 - macro for meta data collectors (beautification)
 - some more comments

The required changes for iproute2 can be pulled from:
  bk://tgr.bkbits.net/iproute2-tgr

The iproute2 part still has quite some potential for improvements to
ease usability though.

Cheers, Thomas