Update row_step when using copyPointCloud on PCLPointCloud2

Updates the row_step field on the output PCLPointCloud2 to reflect
changes in point cloud size.
fixed bug in quad mesh construction (wrong index order caused invalid quads)
Merge pull request #226 from dirkholz/fix_quadmesh

fixed bug in quad mesh construction (wrong index order caused invalid quads)
Merge pull request #222 from dimatura/copypointcloudfix

Update row_step when using copyPointCloud on PCLPointCloud2