Improve documentation of mf-last-modified module

Create keys lookup object to allow better grepping
Document function

Change-Id: I7009cbe7aea33eb4e739827da403bc843de1816a
Localisation updates from http://translatewiki.net.

Change-Id: I75392171bce9ab8939c9a076d07f950e10cb01ab
Merge "Improve documentation of mf-last-modified module"
Merge "Localisation updates from http://translatewiki.net."