evolve: store the old other divergent node after relocation in evolvestate
When the content-divergent changes are on different parents and we relocate of
the node to the parent of another one, we get a new other-divergent node. We
still need to store the older other-divergent in evolvestate so that we can use
that information.
Doc is generated with sphinx.
You can generate the doc with:
```
make
```
# Tutorials
For updating the tutorials, you need to have the docgraph extension installed
(https://pypi.python.org/pypi/hg-docgraph).
Then run the test-topic-tutorial.t and test-tutorial.t to update the output if
needed.
You'll need the dot binary (likely installed by the graphviz package in your
package manager) in order to have graphviz graphs rendered in the html output.
Simply run make in the docs directory should takes care of the conversion of
the tutorial .t files into .rst files. Then sphinx should do the rest of the
jobs by rendering graphviz graphs.