Added build script for coupled MOOSE+Nek5000 example

This includes a script (examples/template_example/build_coupled_nek.sh) for building the Nek5000 libraries and MOON.  The script also deletes/updates the Nek5000 configuration files.  

.gitignore is updated to include build and run artifacts from Nek5000.

See merge request !7

Added updated makenek



See merge request !6

Updated makenek to work with MOON's template_example



See merge request !5

Additional changes needed to makenek to avoid
clobbering the template example Makefile

NekExecutioner and NekTimtestepper

This PR added a:
* NekExecutioner and
* NekTimestepper
Which call subroutines from libnek5000.

Additionally, it moved src/Nek5000 and src/moose to  the top-level so Makefile is cleaner

TODO: Make sure compilation of MOOSE framework works

See merge request !4

BCFunction gets values from Nek5000 common block

The BCs are set by BCFunction using a value from a Nek5000 common block

See merge request !3

Pre-meeting Examples

These are the examples we have working prior to the meeting with INL.  They include:
* Heat conduction in a 2D circular and 3D cylindrical domain
* A "hello world" example to link Nek and MOOSE

See merge request !2

Test driver

This adds two top-level examples in `moon/examples`
* `ex01_inputfile` is the same as `moose/examples/ex01_inputfile` except the Makefile paths have been updated
* `hello_nek` is the same as `ex01_inputfile` except it compiles `libnek5000.a`, initializes Nek from `eddy_uv.rea` and prints some values from a common block.  After that, it runs `ex01` to completion.

See merge request !1