#977: add immortal initial task suite
#977: add immortal r1 task suite
Improve runtime database query functions

No longer susceptible to `.next()[0]` problem.
#1004: test for handling bad sequence interval
#1004: disallow 2-digit centuries
Merge pull request #1066 from benfitzpatrick/977.immortal-r1-tasks

#977: test suite for immortal R1 tasks
improve error message
Merge pull request #1070 from benfitzpatrick/1004.handle-bad-recurrence-nicely

#1004: handle some bad recurrences nicely
Merge pull request #1067 from matthewrmshin/improve-db-query-funcs

Improve runtime database query functions
Use natural sort order in graph tests.
Merge pull request #1072 from hjoliver/graph-test-sort-order

Use natural sort order in graph tests.
Merge branch 'master' into log-work-restructure