proycon/clam: v3.1

Implemented the ability to share output publicly over a one-time download link to overcome authentication barriers #95 Implemented support for temporary unauthenticated storage (enabled by default) in the Forwarder Defer building of downloadable archives to when temporary storage is accessed Implemented a share option in the interface, using a new ShareView. Implemented the ability to share more persistently. fixes for return mime types on error responses for the storage endpoint Implemented a downloadstorage() method in the client library Forwarders now automatically urlencode the backlink #86 Resolve more variables in Forwarder urls and updated documentation accordingly #86 Various fixes and improvements for OAuth2 and OpenID Connect authentication added OAUTH_CLIENT_URL configuration directive Implemented OAUTH_USERINFO_URL parameter and implemented more general behaviour for getting usernames (email) that should work with OpenID Connect #93 Augmented the interface so things don't get cluttered when there are many viewers for a file #102 Do not serialise empty/unfilled input parameters in CLAM metadata #103 Added utility functions isncname and makencname to check if a string is a valid XML NCName and to make it so if not. Duplicated from the folia library but included here so we don't need an external dependency. Implemented an allowdefault option on viewers, can be used to state that you don't want a feature to be used as default viewer. ensure textstats example also works without external configuration file (it is used as a simple demo case) Implemented ability to read original host from X-Forwarded-Host (#105) Updated dependencies to the latest versions, deprecated Python 3.5 support (use 3.6 or higher