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/Analyzer.cc

@@ -3,9 +3,17 @@
 #include "Analyzer.h"
 #include "Manager.h"
 
+file_analysis::ID file_analysis::Analyzer::id_counter = 0;
+
 file_analysis::Analyzer::~Analyzer()
 	{
 	DBG_LOG(DBG_FILE_ANALYSIS, "Destroy file analyzer %s",
 	        file_mgr->GetComponentName(tag));
 	Unref(args);
 	}
+
+void file_analysis::Analyzer::SetAnalyzerTag(const file_analysis::Tag& arg_tag)
+	{
+	assert(! tag || tag == arg_tag);
+	tag = arg_tag;
+	}