Fix QuickStart for ESP8266

SdFat/examples/QuickStart/QuickStart.ino

   // read any existing Serial data
   while (Serial.read() >= 0) {}
   cout << F("\nSuccess!  Type any character to restart.\n");
-  while (Serial.read() < 0) {}
+  while (Serial.read() < 0) {
+    SysCall::yield();
+  }
 }

SdFat/src/SdSpiCard/SdSpiESP8266.cpp

  * \param[in] n Number of bytes to send.
  */
 void SdSpi::send(const uint8_t* buf , size_t n) {
-  // Adjust to 32-bit alignmented.
+  // Adjust to 32-bit alignment.
   while ((reinterpret_cast<uintptr_t>(buf) & 0X3) && n) {
     SPI.transfer(*buf++);
     n--;