3.25 - Slimmer Diffs

• Upgrade to 3.25
• Explain route-specific substates #509
• Small fixes (#507, #508)

The biggest changes is that I slimmed down code diffs to include less of the context.

In previous versions, if anything changed in a file, the whole file was inserted as a code diff. Starting with this version, only 5 lines at each side are added. This results in much less space being taken by code diffs, and hopefully doesn't reduce readability.

The difference can sometimes be dramatic:

Code diff in 3.24:

Code diff in 3.25:

This improvement required a lot of changes behind the scenes, so let me know (you can create an issue here) if you come across weird diffs.