many many small changes

switched to the new logging here and there
some cleanups
worked  on i2S
base class for files
id3 parsing

ext/sd/fat32/DirHandle.h

@@ -75,7 +75,7 @@ namespace FAT32 {
 		bool hasExtension(const char* ext) const {
 			const size_t len = strlen(ext);
 			if (len > 3) {return false;}
-			for (int i = 0; i < len; ++i) {
+			for (size_t i = 0; i < len; ++i) {
 				if (asciitolower(entry.ext[i]) != asciitolower(ext[i])) {return false;}
 			}
 			for (int i = len; i < 3; ++i) {