Stopped PG from sending mathjax script elements.
Merge branch 'develop' of https://github.com/openwebwork/pg into develop
Merge branch 'develop' of https://github.com/openwebwork/pg into develop

# By Geoff Goehle (7) and others
# Via Geoff Goehle (5) and others
* 'develop' of https://github.com/openwebwork/pg:
  If a problem value is negative, then don't display points (used in library browser).
  Update PGessaymacros.pl
  Backport pull request #54 (allow errors from adaptive parameters to appear in the message area)
  removing scrubber
  Update PGessaymacros.pl
  Added to documentation.
  Removed problemPreserveAnswers from anywhere I could find it.
  Implemented Davide's suggestions.
  Fixed 2703 in the manner suggested by Mike.  I commented out character escaping in "problemPreserveAnswer.pl" because it is done earlier now.
  Changed the behavior of "always_show_hint" and "always_show_solution" permission settings so that they do not take effect when generating a hardcopy.
  Adding new matrix macro files.
Merge branch 'develop' of https://github.com/openwebwork/pg into develop

# By Michael Gage (27) and others
# Via Geoff Goehle (15) and others
* 'develop' of https://github.com/openwebwork/pg: (56 commits)
  added option to have HTML table cells use th instead of td for accessibility purposes
  Move ANS() call to correct place for MathObjects (so it doesn't get called for other types of answer checkers).  Resolves issue in pull request #101.
  Fix problem with Context not being called as a function, and make sure MathObjects are loaded.  Fixs bugzilla 3060, and Geoff's issue from pull #101.
  changed version and copyright date
  Fixed a bug with variables in PGstatisticsGraphMacros.pl not being properly defined.
  Fixed the definition of pi in the PGstatisticsmacros.pl file.
  Added class needed to make mathview work with essay questions
  Removed double inclusion of applet macros script files.
  Fixed the definition of pi in the PGstatisticsmacros.pl file.
  Fixed a bug with variables in PGstatisticsGraphMacros.pl not being properly defined.
  Make sure $result always has a value (avoids problem when adaptive parameters can be found in comparison).
  Add wwM ad lrM to the noInherit values (these are cached MatrixReal1 instances, so should not be passed on as inherited values).
  Remove compoundProblem4.pl and replace with compountProblem5.pl
  Fix problem with answer rules in answer arrays.  Fix several variable name warnings.
  Make Formula and Compute return ImplicitPlane objects when appropriate.  This allows ImplicitPlanes to be used in lists.
  Use pg->debug_message for diagnostic output
  Fix complex output so that parentheses are used when the complex number is being subtracted.
  If a problem value is negative, then don't display points (used in library browser). (cherry picked from commit 723d872e65fecb37865d248365d142b389b89543)
  Added to documentation. (cherry picked from commit 0dd7c5590b10cafdfd6b912d0ff2ef6d4dd3367d)
  Fix typo in PG/Translator.pm replacing END_PGML_SOLUTION  with END_PGML_HINT
  ...