In the middle of Zone Effect grid #193.
Minor fix in xml2sqlite script: it is not mandatory to give a probability distribution a name.
Showing the correct ZoneEffect values, but they can't be edited.
xml2sqlite script now handles Histogram type probability functions.
xml2sqlite script fixes to reflect the data model changes in issue https://github.com/NAVADMC/SpreadModel/issues/193.
Working auto-update javascript for Zone Effect Assignment closes #193
Working auto-update javascript for Zone Effect Assignment closes #193
C code SQL query fixes to reflect the data model changes in issue https://github.com/NAVADMC/SpreadModel/issues/193.
Fix to read histogram type PDFs from the database: now properly checks graph_id and sorts on x instead of the deprecated point_order column.
xml2sqlite script now fills in names for all PDFs and rel charts, even ones that didn't have names given in the XML, as discussed with @josiahseaman over email Aug 15.
Minor: one no-longer-needed variable deleted.
Cleanup
Zone stat breakdown partially working for #197.  Discovered bug #198
No Background Zone.  Speculative fix for #198
Small simplification to unit.c ported from old NAADSM 4 code: quarantine and destroy requests become just booleans.
added setting to skip migrations for tests. added check to delete_all_outputs to not remove workspace folder if no scenario folder exists. changed file location in test_population_link so it passes.
changed name of variable in delete_all_outputs to be more descriptive. updated gitignore with cache directory from build results.
Merge branch 'master' into fix-python-tests
added tests to indicate what should happen when a new Population is created with an invalid source file. Refs #189
Basic multi png graph display working for Zones #197