*: add "noexcept" to many, many function prototypes

This eliminates some overhead, because the compiler doesn't need to
consider these functions throwing.

src/input/plugins/FileInputPlugin.cxx

@@ -45,7 +45,7 @@ public:
 
 	/* virtual methods from InputStream */
 
-	bool IsEOF() override {
+	bool IsEOF() noexcept override {
 		return GetOffset() >= GetSize();
 	}