Allow method groups in inline handlers

[Kaliumhexacyanoferrat]

As an application developer, I would like to use method groups in signatures of method definitions, so that I do not need to repeat the arguments unnecessarily.

Example

var webservice = Inline.Create()
                       .Put(WriteFile);

static void WriteFile(Stream input) { }

Acceptance criteria

• The feature works for both code generation and reflection
• The feature is documented on the GenHTTP website
• The feature is covered by acceptance tests