Cleanup the code and unified everything (except the macros) under the akerr_ namespace

tests/err_trace.c

@@ -1,17 +1,17 @@
 #include "akerror.h"
 
-ErrorContext *func2(void)
+akerr_ErrorContext *func2(void)
 {
     PREPARE_ERROR(errctx);
     ATTEMPT {
-	FAIL(errctx, ERR_NULLPOINTER, "This is a failure in func2");
+	FAIL(errctx, AKERR_NULLPOINTER, "This is a failure in func2");
     } CLEANUP {
     } PROCESS(errctx) {
     } FINISH(errctx, true);
     SUCCEED_RETURN(errctx);
 }
 
-ErrorContext *func1(void)
+akerr_ErrorContext *func1(void)
 {
     PREPARE_ERROR(errctx);
     ATTEMPT {