doc: minor editing and more explicit contractions

NS: stabilization added to doc

Thanks-to: Valeria Barra <valeriabarra21@gmail.com>

NS: a correction in documentation

Navier-Stokes - fix indexing bug

Merge pull request #477 from CEED/jed/mtune-native

make: MARCHFLAG: try -march=native, -mcpu=native, then skip (fix #467)

make: MARCHFLAG: try -march=native, -mcpu=native, then skip (fix #467)

Pass OPT from top-level to examples/* that need OPT set.

Reported-by: Yohann Dudouit <dudouit1@llnl.gov>

Style - run make style

Merge pull request #475 from CEED/jeremy/make-style-fix

Fix Make Style (....Again)

Merge pull request #468 from CEED/jeremy/multigrid-coarse

Multigrid - use GAMG, update comments

PETSc - BP/multigrid variable consistency

PETSc - homogonize qf/op variable names

Style - use component array for DMAddBoundary in navierstokes

PETSc - drop unused struct members in sphere example

Style - fix function indentation for navierstokes

Style - fix pointer alignment for setupsphere

make style

Style - add NOPAD directive to fix make style again

Add citation and bib info

Homogenize all section headers style to 40 chars

Use consistent section headers style

This is not only for consistency sake, but it also allows for easy visualization of section breaks

Slightly improve doc of bpssphere

Multigrid - create fineLevel = numLevels - 1 variable for readability

doc: expand exposition on coordinate transformations and metric tensors

Simplify explicit pseudoinverse calculation in bpssphere setup.

Multigrid - use one mat shell for prolong/restrict

PETSc - set GET_DIAGONAL for bps