- markup codingStyleGuide.org examples so they actually indent correctly

- use 'Info<<' as per codingStyleGuide instead of 'Info <<'

- use first() method in some places as well where it helps clarity

- there are a few remaining cases: git grep 'size()-1]'

- in preparation for adding an optional '-reconstruct' to a few utilities
  re-use as -lreconstruct library

- move related stuff there too
      src/decompositionMethods/decompositionMethods
      -> src/parallel/decompositionMethods

- added missing namespace qualifiers

and other unit conversion functions as they are required e.g. slug <-> kg.

- note left utilities/mesh/advanced/collapseEdges/collapseEdges.C as-is.
  It looks suspicious, but the change was recent, so maybe it means something

the include file back to mathematicalConstants.H to make upgrading code slightly easier.

which need this functionality.  Solvers will now check the correctness of the BCs on
read.