Fix ESP8266 crashes with receiver enabled

This should fix #46

RCSwitch.cpp

@@ -40,6 +40,15 @@
     #define memcpy_P(dest, src, num) memcpy((dest), (src), (num))
 #endif
 
+#ifdef ESP8266
+    // interrupt handler and related code must be in RAM on ESP8266,
+    // according to issue #46.
+    #define RECEIVE_ATTR ICACHE_RAM_ATTR
+#else
+    #define RECEIVE_ATTR
+#endif
+
+
 /* Format for protocol definitions:
  * {pulselength, Sync bit, "0" bit, "1" bit}
  * 
@@ -59,7 +68,11 @@
  *
  * These are combined to form Tri-State bits when sending or receiving codes.
  */
+#ifdef ESP8266
+static const RCSwitch::Protocol proto[] = {
+#else
 static const RCSwitch::Protocol PROGMEM proto[] = {
+#endif
     { 350, {  1, 31 }, {  1,  3 }, {  3,  1 } },    // protocol 1
     { 650, {  1, 10 }, {  1,  2 }, {  2,  1 } },    // protocol 2
     { 100, { 30, 71 }, {  4, 11 }, {  9,  6 } },    // protocol 3
@@ -621,10 +634,13 @@ static inline unsigned int diff(int A, int B) {
 /**
  *
  */
-bool RCSwitch::receiveProtocol(const int p, unsigned int changeCount) {
-
+bool RECEIVE_ATTR RCSwitch::receiveProtocol(const int p, unsigned int changeCount) {
+#ifdef ESP8266
+    const Protocol &pro = proto[p-1];
+#else
     Protocol pro;
     memcpy_P(&pro, &proto[p-1], sizeof(Protocol));
+#endif
 
     unsigned long code = 0;
     const unsigned int delay = RCSwitch::timings[0] / pro.syncFactor.low;
@@ -655,7 +671,7 @@ bool RCSwitch::receiveProtocol(const int p, unsigned int changeCount) {
     return true;
 }
 
-void RCSwitch::handleInterrupt() {
+void RECEIVE_ATTR RCSwitch::handleInterrupt() {
 
   static unsigned int changeCount = 0;
   static unsigned long lastTime = 0;