A set of file analysis extensions.

- Enable manager to associate analyzers with a MIME type. With that,
  one can now say enable all analyzers for, e.g., "image/gif". This is
  exposed to script-land as

    Files::add_analyzers_for_mime_type(f: fa_file, mtype: string)

  For MIME types identified via libmagic, this happens automatically
  (via the file_new() handler in files/main.bro).

- Extend the analyzer API to better match that of protocol analyzers:

    - Adding unique analyzer IDs so that we can refer to instances
      from script-land.

    - Adding subtypes to Components so that a single analyzer
      implementation can support different types of analyzers
      internally.

    - Add an analyzer method SetTag() that allows to set the tag after
      construction.

    - Adding Init() and Done() methods for consistency with what other
      classes offer.

- Add debug logging to the file_analysis stream.

TODO: test cases missing for the new script-land functionality.

src/file_analysis/Component.h

@@ -40,8 +40,14 @@ public:
 	 * from file_analysis::Analyzer. This is typically a static \c
 	 * Instatiate() method inside the class that just allocates and
 	 * returns a new instance.
+	 *
+	 * @param subtype A subtype associated with this component that
+	 * further distinguishes it. The subtype will be integrated into the
+	 * analyzer::Tag that the manager associates with this analyzer, and
+	 * analyzer instances can accordingly access it via analyzer::Tag().
+	 * If not used, leave at zero.
 	 */
-	Component(const char* name, factory_callback factory);
+	Component(const char* name, factory_callback factory, Tag::subtype_t subtype = 0);
 
 	/**
 	 * Copy constructor.