Exchange Calendar Adapter using impersonation activated by default. A

master username and master password (which are used to log in to the
exchange server) need to be set in the portlet.xml preferences. All
users use these master values and their uportal username is the value
used for impersonation.
2) A bugfix for caching of calendar events; Etags are now part of the ajax
request url.
todo - internationalize like https://github.com/Jasig/CalendarPortlet/commit/f27c81e4d26185cca3f29d63b4c38d2f2b9f24ed#diff-f860bb203b65fa639f898391a502538bR244