[PLYReader] Fix bad orientation & origin propreties

[VictorLamoine]

Fixes #626

See pcl::PLYReader::read

When pcl::PLYReader::read is called, the orientation & origin of the cloud are specified.
But without the fix, the value passed is modified and the orientation_ proprety remains unmodified.

The same is happening with origin and origin_

Is that right @nizar-sallem ?

[taketwo]

That simple!

By the way, this bug would never happen if the input parameters origin and orientation were const-qualified. Actually, what about adding consts in this pull request?

[VictorLamoine]

I agree they should be const but these parameters not defined as const in file_io.hpp (and ply_io derives from file_io)

Changing the parameters to const means changing this for every derived class; which should be done in an other pull request IMO.

[taketwo]

Makes sense. Then perhaps you could send such a pr some time later for 1.8.0.

[VictorLamoine]

@taketwo My pull request was considering that origin and orientation were inputs, but it's not the case everywhere, for example in a PCD file the origin/orientation can be defined so in that case the parameters should be overwritten (in that case they are output).

So I don't think it's possible to make origin and orientation const in the parameters of the read function.