Fix insert sort for machine translations
Smarter select of related fields for changes

We need to explicitely list relations, to get over NULL fields and fetch
required depth. All those values are needed to print list of changes, so
they would have to be fetched anyway.
Use reverse instead of fetching profile

Fetching profile is expensive and we actually do not need any fields
from it - it just wrapped access to getting profile URL.
Fetch user data together with top contributins
Select related projects for subproject, we will use them anyway
Optimize queries on user page
Correct title for changes page
Setting version to 1.6
Document changes