Bug 12463 - Capitalization: Calendar tool, headings for different types of holidays

There are several instances of incorrect capitalization in the Calendar
tool. This patch corrects them.

To test, apply the patch and go to Tools -> Calendar. Headings and
labels on the page should have correct capitalization.

Signed-off-by: Juhani Seppälä <jseppal@student.uef.fi>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
String changes in the template, no problems found.

Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>