src: update version to 0.5

Changed since v0.4:
  - added a license file
  - added build rules for ALT Linux
  - improved detection of some CP2102 devices
  - small doc cleanups

Author: wtarreau

src/bt.c

@@ -54,7 +54,7 @@
 #define MARGIN  1024
 
 #ifndef VERSION
-#define VERSION "0.4.0"
+#define VERSION "0.5.0"
 #endif
 
 #ifndef MIN