diskio.status() more robust (stops at newline char instead of overwriting buffer), diskio.f_open better detects error status

compiler/res/prog8lib/diskio.p8

@@ -208,6 +208,7 @@ close_end:
         c64.SETLFS(11, drivenumber, 0)
         void c64.OPEN()          ; open 11,8,0,"filename"
         if_cc {
+            if c64.READST()==0 {
                 iteration_in_progress = true
                 have_first_byte = false
                 void c64.CHKIN(11)        ; use #11 as input channel
@@ -219,6 +220,7 @@ close_end:
                     }
                 }
             }
+        }
         f_close()
         return false
     }
@@ -394,10 +396,12 @@ _end        rts
 
         while not c64.READST() {
             @(messageptr) = c64.CHRIN()
+            if @(messageptr) in "\r\n"
+                break
             messageptr++
         }
-
         @(messageptr) = 0
+
 done:
         c64.CLRCHN()        ; restore default i/o devices
         c64.CLOSE(15)