Kokkos Array: Added documentation and comments to kokkos/linalg.

kokkos/linalg is a new linear algebra "subpackage" that depends on
Kokkos Array.  (I put "subpackage" in quotes because we haven't yet
added the CMake machinery to make it a subpackage.)  This commit adds a
lot of public documentation to kokkos/linalg, as well as a few "FIXME"
comments pointing out issues for us developers to address later.
Teuchos: Improved public documentation for ArrayRCP and ArrayView.
Teuchos: Added partial specialization of ArrayRCP for const T.

This parallels the partial specialization of ArrayView for const T.
It should fix compiler warnings for the conversion operator
"operator ArrayRCP<const T> () const", which have been an issue on
PGI builds.
Tpetra: Added missing RowMatrix explicit instantiation for example.

The custom local sparse kernels example requires explicit instantiation
of certain Tpetra classes, in case Tpetra was not built with explicit
instantiation enabled for Scalar=float.  Recent (a few weeks or a couple
months ago) changes to RowMatrix broke this example.  I've added an
explicit instantiation for RowMatrix to the example as well; that fixes
the link errors.

Build/Test Cases Summary
Enabled Packages: Teuchos, KokkosArray, Tpetra
0) MPI_DEBUG => Test case MPI_DEBUG was not run! => Does not affect push readiness! (-1.00 min)
1) SERIAL_RELEASE => Test case SERIAL_RELEASE was not run! => Does not affect push readiness! (-1.00 min)
2) MPI_DEBUG_SS => passed: passed=191,notpassed=0 (4.49 min)
3) SERIAL_RELEASE_SS => passed: passed=147,notpassed=0 (0.39 min)
Other local commits for this build/test group: 6a102d0, a522ab4, 26a78e6
MueLu: fix shadow warning
Stokhos:  Reduce warp counts to prevent debug-mode launch failures.

A few of the KokkosArray SPMV kernels failed in debug mode because of
using too many registers.  For a debug mode, I reduced the number of
warps to prevent this.
Minor edits to clean up AdaptManager logic.

Added ability to prime entity names in stk_io.
Compile fix for BG/Q

Build/Test Cases Summary
Enabled Packages: NOX, Piro, SEACAS, STK
Enabled all Forward Packages
0) MPI_DEBUG => passed: passed=178,notpassed=0 (16.60 min)
1) SERIAL_RELEASE => passed: passed=178,notpassed=0 (9.96 min)
2) MPI_RELEASE_SS => passed: passed=206,notpassed=0 (6.77 min)
Kokkos: Added Compat subpackage.

The Compat subpackage will handle those aspects of compatibility between
Kokkos Classic and Kokkos Array that are relevant to Tpetra.  For
example, it will include conversion operators between Teuchos::ArrayView
and Kokkos Array Views, so that Tpetra can use Kokkos Array Views inside
but continue to present the same interface for backwards compatibility.

Build/Test Cases Summary
Enabled Packages: KokkosArray, KokkosCompat
0) MPI_DEBUG => Test case MPI_DEBUG was not run! => Does not affect push readiness! (-1.00 min)
1) SERIAL_RELEASE => Test case SERIAL_RELEASE was not run! => Does not affect push readiness! (-1.00 min)
2) MPI_DEBUG_SS => passed: passed=2,notpassed=0 (3.06 min)
3) SERIAL_RELEASE => passed: passed=2,notpassed=0 (2.34 min)
Kokkos : fix simple-build pthread flag.