Segmentation fault during volume projection

When I requested the three projections of the volume reconstructed from an input mesh, the XY projection was computed and saved to disk, but the XZ projection failed and caused a segmentation fault. This issue occured on macOSX with the demo neuron1 mesh.

```
./bin/ultraMesh2Mesh --mesh neuron-1.obj --output-directory testing-datasets/demo4 --export-obj-mesh --ignore-marching-cubes-mesh --ignore-laplacian-mesh --project-xy --project-xz --project-zy --resolution 1024

----------------------------------------------------------------------------------
------------------------------| Creating Context |------------------------------
----------------------------------------------------------------------------------

WARNING: The bounding box of the volume will be computed on the fly

----------------------------------------------------------------------------------
--------------------------------| Ultralizing |--------------------------------
----------------------------------------------------------------------------------

NOTE: Output Directory [ /Volumes/Computer/testing-datasets/demo4 ]

NOTE: Volume resolution [1024], Largest dimension [344.103149]

----------------------------------------------------------------------------------
----------------------------| Creating Volume Grid |----------------------------
----------------------------------------------------------------------------------

NOTE: Volume Dimenions [ 798 x 513 x 1024 ] : [ 295.102295 x 189.448395 x 378.513428 ]

----------------------------------------------------------------------------------
----------------------------| Surface Voxelization |----------------------------
----------------------------------------------------------------------------------

Creating Volume Shell [798 x 513 x 1024]
Parallel Rasterization
* Progress │▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒│ (100.00 %)
* Time | 0.347741 Seconds

Rasterization Stats.
* Time | 0.34776 Seconds

----------------------------------------------------------------------------------
-----------------------------| Projecting Volume |-----------------------------
----------------------------------------------------------------------------------

Compositing Projection(s)
XY Projection
* Progress │▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒│ (100.00 %)
* Time | 7.19442 Seconds

XZ Projection
* Progress │▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒│ (100.00 %)
[1] 42550 segmentation fault ./bin/ultraMesh2Mesh --mesh /Volumes/Computer/testing-datasets/neuron-1.obj
```

Reproduce the failure with bin/ultraMesh2Mesh using the neuron-1.obj command shown in the issue, focusing on the transition from the completed XY projection to XZ projection. Done means the XZ projection no longer causes a segmentation fault and the requested XY, XZ, and ZY projections are saved successfully.

Written by the indexing model from the issue text.