Elm-doc

Breaking changes
* Indirect deps are no longer included in the generated docs
* Elm is no longer installed and used automatically when no `--elm-path` is specified

Fixes
* Fixes ambiguous import error when a project's direct and indirect deps share the same module name (55)
* Invoke rsync with `--ignore-errors` to power through errors like "IO error encountered -- skipping file deletion" which is silently dropped by rsync

New
* Support `-h` as a flag for displaying help
* Run Travis tests against Python 3.7

Breaking change:

* The rsync command is now required to run elm-doc in order to support multiple source directories cleanly.

Note: I'm sorry I seem to have lost the commit that bumps the version number in `setup.py`. If it's causing problems, let me know and I'll try to figure it out.

Since this version includes significant code change in order to rewrite `port` declarations as part of the build, I'm marking this as a pre-release. While it has been tested against a fairly large codebase of Elm, there may be edge cases that elm-doc can't handle.

Backwards incompatible changes

- Drop Python 3.4 support
- Drop Elm 0.18 support
- Require `--fake-license` flag to be specified when invoking elm-doc. Please see the updated README.md for details
- `--elm-make` flag is not called `--elm-path`

New behaviors

- Elm 0.19 is the new & only Elm version supported
- Create an `.elm-doc` directory at the root of the target project as the build directory, which can be changed with `--build-dir`
- Do not require any C extension to be built when installing elm-doc

Fixed:

- 12 Build output was not relocatable

Fixes

- 11 Pin package.elm-lang.org (documentation renderer) version to 0.18.0

Breaking change

Positional arguments that follow the first positional argument are now considered paths to include. Previously, they were passed in to `doit.doit_cmd.DoitMain.run`. You should now use `--doit-args 'args separated by space'` for that purpose.

Explicitly specified paths to include take precedence over the `--exclude` argument: docs are generated/validated even if the paths match the `--exclude` module pattern.

Added

`--force-exclusion` flag to reverse the behavior described above: explicitly specified paths to include get ignored if they match the `--exclude` module pattern.