Revert "Changed the credit terminology to scoring."

This reverts commit c6f4adc69eeaf27cb21ada587a6a6cd96a802a90.
Revert "Changed how the reduced credit checker works.  It now has a date provided to it (rather than a reduced credit scoring period)."

This reverts commit 788e39a324435a4dd6be2ab1314113b31cc4173b.
-  Added check for undefined variable in unionTables.pl
Add missing super class to ImplicitPlane::formula.  Bugzilla 3125.
Merge pull request #129 from dpvc/patch-implicit-plane

Add missing super class to ImplicitPlane::formula.  Bugzilla 3125.

This fixes the problem from the bug
Merge branch 'release/2.9' of https://github.com/openwebwork/pg into bugfixes

Conflicts:
	macros/unionTables.pl
Merge pull request #128 from goehle/bugfixes

Bugfixes
Merge pull request #107 from KellyBlack/bugfix_create_temp_data_file

Fixed bug in how the files used to keep temporary data files are created...

This doesn't change anythign bug fixed syncronicity between master and release/2.9
Added codeshard class to inputs produced by NAMED_ANS_RULE_EXTENSION for use by mathview