support end of line insertion now that selection length can be 0
Merge pull request #875 from jay-hodgson/release-34

SWC-1223: support end of line insertion now that selection length can be 0
SWC-1223: another edge case, empty text
Merge pull request #876 from jay-hodgson/release-34

SWC-1223: another edge case, empty text
Merge branch 'release-34' into develop

Conflicts:
	src/main/java/org/sagebionetworks/web/client/DisplayUtils.java
	src/test/java/org/sagebionetworks/web/unitclient/DisplayUtilsTest.java