WL-2968 Upgrade to Ambrosia 2.1.20

Reference sakai-2.8 correctly
WL-1328 Add CSV export of student scores
Revert "Merge to Ambrosia for CK by Mallika"

This reverts commit 844416443af36ad2140a4c22832c2cab4941c0b6.

Conflicts:
	ambrosia-impl/impl/src/java/org/etudes/ambrosia/impl/UiHtmlEdit.java
	ambrosia-impl/impl/src/java/org/etudes/ambrosia/impl/UiInterface.java
	ambrosia-library/lib/src/webapp/skin/ambrosia.css
WL-3164 Revert "MN-1193"

Timezone 'features' were not being carried over to the calendar picker that
Ambrosia are using so all dates entered were appearing as invalid.

This reverts commit ac67f210fe6d433b02e18646cc4cf44c2d0d3b8b.
Merge pull request #3 from ox-it/WL-3164

WL-3164 Allow date inputs