(WiP,unstable) Revisit ACC serial/parallel/data

WARNING: Potentially unstable. Consider to use an older commit.

* scanner/parser: Clauses of acc data regions are pushed onto stack
  and made available to embedded acc compute constructs.
  The latter thus have more knowledge of not-explicitly mapped
  data attributes, which helps when a default(none)
  clause is present.

* Look for acc end serial and acc end parallel when processing
  when recording lines for translating such constructs.
  Do not count do loops anymore in this case.

(WiP) Add and or reduction ops