contrib: add execute bit for fixpax.py

contrib: add execute bit for check-py3-compat.py

perf: make start revision configurable for perfrevlog This will help isolate performance characteristics of delta chains.

perf: use standard arguments for perfrevlog We have a convention of using -c|-m|FILE elsewhere for reading from revlogs. Use it for `hg perfrevlog`. While I was here, I also added a docstring to document what this command does, as "perfrevlog" is ambiguous.

test-extension: do not depend on demandimport (issue5012) When demandimport is disabled, the test will fail because extroot/foo.py uses import outside PYTHONPATH. This is bad since we have a PyPy migration plan and it does not support demandimport. Fix by setting PYTHONPATH.

commands: split notes into note containers

remove: quote --force in never deletes note Split Note into a note container

import: reword no hunks partial note Split Note into a note container

merge: reword help to use See help resolve

py3compat: use absolute_import

patch: use absolute_import

mdiff: use absolute_import

scmposix: use absolute_import

scmutil: use absolute_import

scmwindows: use absolute_import

store: use absolute_import