stub method for read.im3d
initial tests for read.im3d
implement and test reading of nrrds in read.im3d
implement and test reading of amiramesh 3d image data by read.im3d
roxygenise
implement basic write.im3d function with support for nrrd

* and round trip test
roxygenise, merge docs for read/write.im3d
Verbatim copy of Write3DDensityToAmiraLattice
normalise write.amiramesh and add to write.im3d
define boundingbox generic and bring in verbatim copy of getBoundingBox
Full implementation of BoundingBox methods
doc fix
roxygenise write.amiramesh
Teach read.amiramesh what to do when no sections at all are required
read.im3d has new ReadData paramater
check() fixes
Add boundingbox.character method
add voxdims.im3d method, thereby simplifying voxdims.default
return NULL if no density supplied to boundingbox.default
Basic version of im3d() constructor function