Template for the String datatype for Particle Variable was not being used

[pfeerick]

Moved and 'fixed up' the template for the String Partice Variable to OakParticle.h. It looks like it was missed when DarkLotus did his changes in #37. Test code will be added as a second comment. Please stress test and review the code, as it worked for me, but my knowledge of (variadic) templates goes as far as copy, paste and mimic... I've managed to avoid them completely till now ;-O

[pfeerick]

SYSTEM_MODE(SEMI_AUTOMATIC)

int analogvalue = 0;
double tempC = 0;
const char *message = "my name is particle";
String aString = "this is a String!";

void setup()
{
  // variable name max length is 12 characters long
  Particle.variable("analogvalue", analogvalue);
  Particle.variable("temp", tempC);
  Particle.variable("mess", message);
  Particle.variable("mess2", aString);

  // connect to particle now that the variables have been defined
  if (Particle.connected() == false) 
  {
    Particle.connect();
  }

  pinMode(A0, INPUT);
}

void loop()
{
  // Read the analog value of the sensor (TMP36)
  analogvalue = analogRead(A0);
  //Convert the reading into degree celcius
  tempC = (((analogvalue * 3.3)/4095) - 0.5) * 100;
  delay(200);
}