Merge changes from origin/7.1

Merge changes from origin/7.1

0e048a5 Clarified error message (#12583)
d0af7d1 Add async-supported to all servlets to enable push testing (#12573)
1de4389 Use JUnit 4.11 in all modules (#12572)
d6954f8 Include TestBench 3.1.1 in the project (#12572)
cdb9a49 Enable native scrolling in all iOS versions newer than 5, not just iOS 6 (#12324)
0e2780a Ensure string converter is always set
cf796e2 Add v-iosN classname for all iOS versions instead of just N=6 (#12324)
46ac1e6 Update release notes to more closely be like 7.0.x (#12544)
d9f204f PostLayoutListener javadocs (#12562)
c7aaa04 Don't try to cast a connector to Widget. Fixes #12619

Change-Id: Icff34ba20a330e633c1b29ca8fd77d84b79841f5