Repository from hell (gitk stresstest)

Just in case someone wants to see how gitk performs on a tree with 8 main branches and littered with backports (single-patch-cross-merges between branches), have a look at: git://git.cuci.nl/pike

Start gitk with --all to view it in full glory (of course).

Some notes:
- The branches are interconnected through their first-parents as follows:
   v0 --o--o--o--o--o--o--o-------- 7.7
         \  \  \  \  \  \  \
          \  \  \  \  \  \  o------ 7.6
           \  \  \  \  \  o-------- 7.4
            \  \  \  \  o-------- 7.2
             \  \  \  o-------- 7.0
              \  \     \
               \  \     o------ nt-tools
                \  o-------- 0.6
                 o--------- 0.5
- As one can see, gitk deals with the numerous backports just fine,
  except that it uses a bit (too) much screen realestate perhaps at
  times.
- I find the Branches, Follows and Precedes display of gitk confusing
  on occasion, when inside this entanglement of backports.
  Most notably, IMO:
  + It should only show the main branch you're on (i.e. when determining
    the branch, please use the first-parent information only, and
    disregard any parents that come from merges).
  + The "Follows" and "Precedes" list might look cleaner when
    displaying only the tags which are on the same main branch the
    current commit is part of.