Added unique prefix to preprocessor macros and updated their usage

Using generic preprocessor macros like HOST opens the risk of another
library or the user trying to define the same macro. To correct this,
I prefixed all macros for the YouTubeAPI with YTAPI_ so they're unique.

Also removed unused macros, replaced the hardcoded hostname with the
existing macro, and pulled out the hardcoded timeout.

Author: PhirePhly

src/YoutubeApi.cpp

@@ -34,15 +34,15 @@ String YoutubeApi::sendGetToYoutube(String command) {
 	unsigned long now;
 	bool avail;
 	// Connect with youtube api over ssl
-	if (client->connect(HOST, SSL_PORT)) {
+	if (client->connect(YTAPI_HOST, YTAPI_SSL_PORT)) {
 		// Serial.println(".... connected to server");
 		String a="";
 		char c;
 		int ch_count=0;
 		client->println("GET "+command+"&key="+_apiKey);
 		now=millis();
 		avail=false;
-		while (millis()-now<1500) {
+		while (millis() - now < YTAPI_TIMEOUT) {
 			while (client->available()) {
 				char c = client->read();
 				//Serial.write(c);
@@ -83,7 +83,7 @@ String YoutubeApi::sendGetToYoutube(String command) {
 }
 
 bool YoutubeApi::getChannelStatistics(String channelId){
-	String command="https://www.googleapis.com/youtube/v3/channels?part=statistics&id="+channelId; //If you can't find it(for example if you have a custom url) look here: https://www.youtube.com/account_advanced
+	String command="https://" YTAPI_HOST "/youtube/v3/channels?part=statistics&id="+channelId; //If you can't find it(for example if you have a custom url) look here: https://www.youtube.com/account_advanced
 	String response = sendGetToYoutube(command);       //recieve reply from youtube
 	DynamicJsonBuffer jsonBuffer;
 	JsonObject& root = jsonBuffer.parseObject(response);

src/YoutubeApi.h

@@ -26,11 +26,9 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 #include <ArduinoJson.h>
 #include <Client.h>
 
-#define HOST "www.googleapis.com"
-#define SSL_PORT 443
-#define HANDLE_MESSAGES 1
-#define MAX_BUFFER_SIZE 1250
-
+#define YTAPI_HOST "www.googleapis.com"
+#define YTAPI_SSL_PORT 443
+#define YTAPI_TIMEOUT 1500
 
 
 struct channelStatistics{