Add a table that shows the spread of disease occurrences over country and year, for a particular disease group. All non-discarded disease occurrences are considered.
Merge branch 'master' into 319-disease-spread-table

Conflicts:
	src/PublicSite/src/uk/ac/ox/zoo/seeg/abraid/mp/publicsite/web/admin/AdminDiseaseGroupController.java
	src/PublicSite/test/uk/ac/ox/zoo/seeg/abraid/mp/publicsite/web/admin/AdminDiseaseGroupControllerTest.java
Fixes following review
Typo
Fix following Travis failure
Remove unused import
Fix following Travis failure
Merge pull request #266 from SEEG-Oxford/319-disease-spread-table

Disease occurrence spread table