Add missing assignment operator overload (#3971)
Start work on SolutionRasterizer (#3972)
Add XYZ processing logic (#3972)
Check if x,y,z columns were read, add LF (#3972)
Rewrite XYZ file header with updated number of atoms (#3972)
Merge pull request #3973 from dschwen/ebop_3971

Add missing assignment operator overload
Add test, fix line parse check (#3972)
Merge pull request #3974 from dschwen/solutionxyz_3972

Add SolutionRasterizer with test
Adding a test which reads into an elemental variable instead of a
nodal variable.

The elemental variable field looks a lot more like the original image
when you have 1 pixel/element.

[original](https://drive.google.com/file/d/0B9BK7pg8se_iU2xFS19aUVVPOGs/edit?usp=sharing)
[elemental](https://drive.google.com/file/d/0B9BK7pg8se_iOUNSUlpfM1RNZUE/edit?usp=sharing)
[nodal](https://drive.google.com/file/d/0B9BK7pg8se_ieEw2S25VUU15S2M/edit?usp=sharing)

Refs #3544.
Adding initial test of reading an image.
Drop this commit.

Adding debugging to ImageFunction.C...
Adding ability to customize whether the NodalFloodCount threshold
check is a less-than or greater-than check.

By default, it is less-than.
Use the new use_less_than_threshold_comparison in new test.
Add CSV filename to fuel.i.

Current order of data is:
timestep, time, volume-of-bubble-1, volume-of-bubble-2, ...
Delete commented-out line.
Use MooseSharedPointers for the file handles.
Avoid multiple lg(N) lookups of the file handle.
Add one more comment.
Delete unnecessary parens.

Add/clarify comment.
Rename variable bubble_it1, there is no bubble_it2...