Replace “package” with “module” in a number of places

Ref #1059
Merge commit 'HEAD@{1}' into develop
Include documentation in the sdist package
Merge branch 'manifest-docs' into develop
Replace u() function with out_u for safer unicode conversion
Convert shortened path to unicode

Fixes #1064
Merge pull request #1065 from ZyX-I/fix-1064

Fix some possible unicode errors
Raise OSError with errno=ENOENT from uv watcher

Fixes #1066
Check that exception from watcher has errno attribute equal to ENOENT
Merge pull request #1067 from ZyX-I/fix-1066

Add proper errno attribute to exception raised by uv watcher
Do not use _POWERLINE_SHORTENED_PATH or unset it shortly after using

Fixes #1068
Include args.config_path in the key

Consider the following script:

    % powerline-daemon -s powerline-test
    % powerline --socket powerline-test -p/dev/null shell left
    Config file not found in search paths (/dev/null): config.json
    % powerline --socket powerline-test shell left
    Config file not found in search paths (/dev/null): config.json

Note the problem: second call to powerline does not use offending path, but it 
still emits the error “Config file not found in search paths”.
Add tests
Merge pull request #1070 from ZyX-I/fix-daemon

Include args.config_path in the key
Merge pull request #1069 from ZyX-I/workaround-1068

Do not use _POWERLINE_SHORTENED_PATH or unset it shortly after using
Allow setting g:powerline_pyeval to PowerlinePyeval for testing
Encode vim statusline to &encoding before returning

Partially fixes #1072
Use proper encoding to convert values in various places

Fixes #1072
Compare bytes() objects in matcher functions

Fixes #1071
Add tests for invalid unicode filenames

Ref #1071