pdoc3/pdoc

Improved module importing / support for namespace packages

Otherwise `pdoc.html_helpers.extract_toc()` doesn't work.

Refs: eda27f3

Even as documented that other types are ignored [1],
it seemed to break on other versions of Python [2].

[1]: https://docs.python.org/3/library/sys.html#sys.path
[2]: https://travis-ci.org/pdoc3/pdoc/jobs/527591043#L218-L270

Maybe avoids problems with modules whose importing
has side effects.

Breaks CLI behavior when modules specified as file paths:
Previously full relative path was considered module path,
now only the basename is.
Thus some tests break.

For easier debugging with breakpoints not stopping
where not needed.

No longer required since the content is no longer
a Python string.

Refs:
* eda27f3
* #57

What was left out in 4faccce

* Change type annotation arrow character

Change from the arrow character used to render the return type annotation from
WIDE-HEADED RIGHTWARDS LIGHT BARB ARROW (http://www.fileformat.info/info/unicode/char/1f862/index.htm)
to the more widely supported
RIGHTWARDS ARROW (https://www.fileformat.info/info/unicode/char/2192/index.htm)

* Use ASCII arrow (->)

Following the discussion in #51

* move main docstring into a file

* move intro paragraph back into source code

* remove backslash

* remove typo

* Revert "remove typo"

This reverts commit 5d2ced5.

Leave formatting for now.

Fixes #53 (comment)

Fixes #53 (comment)

Fixes #43

Deprecations:
* --overwrite  →  -f, --force
* --html-dir   →  -o, --output
* --html-no-source
* --external-links
* --link-prefix

New:
* --config TEMPLATE_OPTION=VALUE

Fixes #6

Refs: #6 (comment)

Maybe an issue in `pdoc.Module.find_class()`.

Refs: 5df06cd ENH: Support Function.params/return type annotations

Fixes #24

Fixes #6
Closes #7

Refs: mitmproxy/pdoc#185
Thanks @osynge.