Adding WEEKLY test category (Trilinos #5962, PHI Kanban #3082)

See updated documentation.
Updated for updated template.

Build/Test Cases Summary
Enabled Packages: TrilinosFramework
Enabled all Forward Packages
0) MPI_DEBUG => passed: passed=116,notpassed=0 (2.50 min)
1) SERIAL_RELEASE => Test case SERIAL_RELEASE was not run! => Does not affect push readiness! (-1.00 min)
Other local commits for this build/test group: f05febf
Adding WEEKLY test category (Trilinos #5962, PHI Kanban #3082)

Build/Test Cases Summary
Enabled Packages: TrilinosFramework
Enabled all Forward Packages
0) MPI_DEBUG => passed: passed=116,notpassed=0 (2.43 min)
1) SERIAL_RELEASE => Test case SERIAL_RELEASE was not run! => Does not affect push readiness! (-1.00 min)
Small doc update.
Skeleton of a TriBITS Overview document
Example of raw CMake project.

This is to contrast with TriBITS.
Moved hello_world lib, exec, test to subdir.
Added simple readme for RawHelloWorld
Remove *.exe and remove some whitespace

Turns out CMake is smart enough to add the *.exe on Windows.

I also removed some vertical whitespace to tighten up.
Adding RawHelloWorld example and discussion.
Adding standard includes for libraries, executbles, tests, etc.

Packages need almost all of these anyway at some point so they might as well
just be included in the top level package include.  This should help avoid
problems that I have seen on some systems and some versions of CMake where if
you miss an include CMake will do strange things.

Note that I would have liked to have avoiding having to include
TribitsPackageMacros.cmake at all in a package's CMakeLiss.txt file but the
current contents of TribitsAddExecutable.cmake set variables that require
package-level scope.  Hopefully I can clean this up soon.
Allowing _ENABLE_EXPORT_MAKEFILES_DEFAULT to be set at project level.
Adding simple TribitsHelloWorld example.
Added mention of TribitsHelloWorld.
Removing extra includes no longer needed
Narrowing excludes and adding exclude for TribitsOverview.out
More compression.
Adding TribitsHelloWorld example.
Some edits.
Adding TribitsExamplejProject directly as a TriBITS example

The best way to push TribitsExampleProject and make it accessable is to add it
directly to the TriBITS source tree.  I believe we can even add acceptance
tests for TriBITS that will build and test TribitsExampleProject.