evolve: store obsmarkers to be deleted in evolvestate
There are operations which don't create a new node rather they just obsolete one
of the unstable node in favour of existing one. In such cases if a further
resolution leads to conflicts and user calls `evolve --abort` or `evolve
--stop`, we might need to delete that obsmarker. So let's store such obsmarkers
in the evolvestate.
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.