Merge pull request #23 from somiaj/update-pg-to-2.20

Update PG to version 2.20 release candidate.

Author: drdrew42

conf/pg_config.yml

@@ -140,6 +140,12 @@ specialPGEnvironmentVars:
   # Size in pixels of dynamically-generated images, i.e. graphs.
   onTheFlyImageSize: 400
 
+  # To enable Rserve (the R statistical server), uncomment the following two
+  # lines. The R server needs to be installed and running in order for this to
+  # work. See http://webwork.maa.org/wiki/R_in_WeBWorK for more info.
+  #Rserve:
+  #  host: localhost
+
   # Locations of CAPA resources. (Only necessary if you need to use converted CAPA problems.)
   CAPA_Tools: $Contrib_dir/CAPA/macros/CAPA_Tools/
   CAPA_MCTools: $Contrib_dir/Contrib/CAPA/macros/CAPA_MCTools/
@@ -231,6 +237,7 @@ modules:
   - [Multiple]
   - [PGrandom]
   - [Regression]
+  - ['Plots::Plot', 'Plots::Axes', 'Plots::Data', 'Plots::Tikz', 'Plots::JSXGraph', 'Plots::GD']
   - [Select]
   - [Units]
   - [VectorField]
@@ -249,8 +256,7 @@ modules:
   - ['Tie::IxHash']
   - ['Locale::Maketext']
   - ['WeBWorK::PG::Localize']
-  - [JSON]
-  - ['Class::Tiny']
+  - ['Mojo::JSON']
   - ['IO::Handle']
   - ['Rserve']
   - [DragNDrop]