all: minor cleanups, update some comments

src/main.cpp

@@ -25,6 +25,8 @@
    <markus@oberhumer.com>               <ezerotven+github@gmail.com>
  */
 
+// main entry, mostly boring stuff; see work.cpp for actual action
+
 #include "conf.h"
 #include "compress.h"
 #include "file.h"