BUG: fix bad environment parsing in foamCreateModuleInclude

- The changes in foamCleanPath introduced for issues (#1007, #1008)
  include quoted output of the cleaned environment variable.
  When used in foamCreateModuleInclude, the quotes make their way
  into the final environment. Avoid this by using the -sh-env
  eval format instead.

- add environment extraction of MANPATH changes