Removed historic Arduino-0012 workaround

Removed #undefs in SoftwareSerial.h that were marked as Arduino 0012 workaround and that broke several macros, including abs.
See arduino#30

Author: florian-schweiger

libraries/SoftwareSerial/src/SoftwareSerial.h

@@ -111,13 +111,4 @@ class SoftwareSerial : public Stream
   static inline void handle_interrupt() __attribute__((__always_inline__));
 };
 
-// Arduino 0012 workaround
-#undef int
-#undef char
-#undef long
-#undef byte
-#undef float
-#undef abs
-#undef round
-
 #endif