export: Default user name to app name

and remove code for deducing current user.

This makes the behavior consistent with Foreman (see #109). Also, I
think folks are more likely to want to run their apps as some
app-specific user, not as the user running export. In fact, some folks
may run `honcho export` on a completely different box than where they
end up running the applications.
Fix GH-101 by removing fragile integration tests

The `tests in honcho/test/integration/test_ports.py` are fragile, as
they rely on processes starting up and echoing something before the
assert fires. They're using a `sleep 1` as a hack to try to make this
more likely, which surely is a sign of a bad test.
Merge pull request #118 from msabramo/GH-101_remove_test_ports

Fix GH-101 by removing fragile integration tests
Merge pull request #111 from msabramo/export_default_user_to_app

export: Default user name to app name
Makefile: clean docs on `make clean`
Move supervisord test into test.export package
Restructure export package
Remove coverage monkeypatch

This isn't really necessary, and causes breakage with newer versions of
coverage.
export: Improve design and test coverage of export

This commit:

- Moves responsibility for I/O back into `honcho.command` rather than
  `honcho.export`.
- Changes exporters so that `#export()` takes a list of
  `honcho.environ.ProcessParams` objects and optional template context.
  This means that concurrency, process naming, and port assignment is
  now much more likely to be consistent between `honcho start` and
  `honcho export`.
- Improves test coverage of the `honcho.export` package.
- Removes a couple more fragile export integration tests.
command: slightly better reporting of I/O errors
Merge pull request #119 from nickstenning/better-export

Improve design and test coverage of export package
Add support for -t/--template option to export

This is a honcho analogue of the corresponding options to `foreman
export` (See http://ddollar.github.io/foreman/#EXPORTING)

This lets you specify a custom Jinja template to be used when exporting
to a supervisord config file.

Fixes: GH-88

See: https://github.com/nickstenning/honcho/issues/88