1. Change "Settings" to "Preferences" in the user menu's "Settings"
category.
2. Move "Shared by me" and "Shared with me" to a new "Share" category in
the main menu to conform with the three main elements of Mahara.

Change-Id: I0af04a22df5d6469c74674225a7c68c642d99281
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>