[Insight-developers] vxl update

[Brad King]

Hi Folks,

I pushed out a topic branch that updates Utilities/vxl from a recent
upstream version:

  https://github.com/bradking/ITK/tree/update-vxl

The topic adds a Utilities/vxl/README-ITK.txt file with instructions to
update vxl in the future.  It uses the git "subtree" merge strategy to
merge a branch containing snapshots of upstream vxl reduced down to the
minimum for vnl.  Future updates will be quite easy using this approach.

I had to resolve quite a few conflicts because several changes were
contributed to both upstream vxl and ITK's vxl over the three years
since the last update.  The changes were slightly different on each side
so the lines conflicted.  I favored the upstream vxl side to make future
updates easier except in cases where the ITK side clearly had
more recent fixes.

I've built and run all tests on 64-bit Linux (gcc 4.4) and 32-bit
Windows (VS9).  I'd appreciate some testing on other platforms.  Due to
the introduction of a new root commit and subtree merges Gerrit may not
be a suitable way to review this topic.  Therefore I pushed it out to
GitHub.

Checkout instructions:

 git remote add bradking https://github.com/bradking/ITK.git
 git fetch bradking
 git checkout -b update-vxl bradking/update-vxl

Thanks,
-Brad