NatLibFi/Annif: Annif 0.40

This is a cleanup and bugfix release that renames some methods and commands but brings no real new functionality. New in this release: #270/#272 The CLI command and REST API method analyze has been renamed to suggest and the CLI command analyzedir to index. Also some internal data structures were renamed accordingly. The idea is to clarify terminology so that from now one analyzing means only the preprocessing (e.g. tokenizing and stemming) done by Analyzers, not the whole operation of assigning/suggesting subjects for a document. For some background, see this post on annif-users #262/#263 Fix some UTF-8 encoding issues, especially on Windows. Now all input files are processed as UTF-8 regardless of the system character set. Credit: @Veldhoen #271 Clean up unused imports and declare transitive dependencies. Credit: @kino