docs: typo in xyzmatrix
Add example for subset.dotprops using Negate

* Closes #145
Add internal cmtk.version function
Fix: xformpoints + some compound CMTK registrations

* there is a bug in versions of CMTK<3.2.2 for streamxform-based
  transformation of some compound registrations. See:
  https://github.com/jefferis/cmtk/commit/209168d892d8980e47
  for details.
add tests for cmtk.version()
document and export cmtk.version
also document nat.cmtk.version option
CHECK: partial arg match fix
Bump version to 1.5.9
failing test using df column to specify subdir

* see bug #148
fix: use df column to specify subdirs

* closes #148
simplify examples for write.neurons

* we don't need the file.path wrapper now
make cmtk.targetvolume generic

* and split off docs from cmtk.reformatx
cmtk.targetvolume should work for im3d/templatebrain

* anything with an as.im3d method should be fine
* could also make a cmtk.targetvolume.templatebrain method if desired
test for im3d functionality of cmtk.targetvolume

* could add a test in nat.templatebrains as well
roxygenise
docs: tidy up cmtk.reformatx
Merge branch 'feature/generic-cmtk.reformatx'

* feature/generic-cmtk.reformatx:
  docs: tidy up cmtk.reformatx
  roxygenise
  test for im3d functionality of cmtk.targetvolume
  cmtk.targetvolume should work for im3d/templatebrain
  make cmtk.targetvolume generic
* closes #147
add failing test for writing with file_sans_ext

* see bug #150
Append ext when file does not already have one

* closes #150