Revert "Remove copyArrayPos." We still need the implementation of copyArrayPos
in feldspar_array.h, but the Frontend things can safely be removed.

This reverts commit 2942c2ec42390998982704f5fb48e4c06a8b246a.

Conflicts:

	lib/Feldspar/Compiler/Imperative/Frontend.hs
Remove copyArrayLen.
Make sure that par and future declare variables in the right scope.
Merge pull request #94 from pjonsson/restore-copyarraypos

Restore copyArrayPos, remove copyArrayLen and make sure to declare variables in right scope