Adding options Analyzer::disable_all to disable all analyzers at

startup.

One can then selectively enable the ones one wants inside a bro_init()
handler.

src/analyzer/Manager.h

@@ -113,6 +113,11 @@ public:
 	 */
 	bool DisableAnalyzer(EnumVal* tag);
 
+	/**
+	 * Disables all currently registered analyzers.
+	 */
+	void DisableAllAnalyzers();
+
 	/**
 	 * Returns true if an analyzer is enabled.
 	 *