Fix type problem

IRSender.h

@@ -51,7 +51,7 @@ class IRSenderBitBang : public IRSender
     void mark(int markLength);
 
   protected:
-    uint _halfPeriodicTime;
+    int _halfPeriodicTime;
 };
 
 #endif

IRSenderBitBang.cpp

@@ -23,7 +23,7 @@ void IRSenderBitBang::mark(int markLength)
 {
   long beginning = micros();
 
-  while(micros() - beginning < markLength){
+  while((int)(micros() - beginning) < markLength){
     digitalWrite(_pin, HIGH);
     delayMicroseconds(_halfPeriodicTime);
     digitalWrite(_pin, LOW);