Added leave server and other stuff

src/Client/Client.js

@@ -226,6 +226,21 @@ class Client extends EventEmitter {
 				})
 		});
 	}
+	
+	leaveServer(server, callback=function(err){}){
+		var self = this;
+		return new Promise((resolve, reject) => {
+			
+			self.internal.leaveServer(server)
+				.then(() => {
+					callback(); resolve();
+				})
+				.catch(e => {
+					callback(e); reject(e);
+				})
+			
+		});
+	}
 }
 
 module.exports = Client;

src/Client/InternalClient.js

@@ -65,6 +65,36 @@ class InternalClient {
 		});
 	}
 	
+	//def leaveServer
+	leaveServer(srv) {
+		var self = this;
+		return new Promise((resolve, reject) => {
+			var server = self.resolver.resolveServer(srv);
+			if(server){
+				
+				request
+					.del(Endpoints.SERVER(server.id))
+					.set("authorization", self.token)
+					.end((err, res) => {
+						if(err){
+							reject(new Error(err.response.text));
+						}else{
+							// remove channels of server then the server
+							for(var chan of server.channels){
+								server.channels.remove(chan);
+							}
+							// remove server
+							self.servers.remove(server);
+							resolve();
+						}
+					});
+				
+			}else{
+				reject(new Error("server did not resolve"));
+			}
+		});
+	}
+	
 	// def login
 	login(email, password) {
 		var self = this;

src/Client/Resolver/Resolver.js

@@ -15,6 +15,21 @@ class Resolver {
 	constructor(internal) {
 		this.internal = internal;
 	}
+	
+	resolveServer(resource){
+		if(resource instanceof Server){
+			return resource;
+		}else if(resource instanceof ServerChannel){
+			return resource.server;
+		}else if(resource instanceof String || typeof resource === "string"){
+			return this.internal.servers.get("id", resource);
+		}else if(resource instanceof Message){
+			if(resource.channel instanceof TextChannel){
+				return resource.server;
+			}
+		}
+		return null;
+	}
 
 	resolveFile(resource) {
 		if (typeof resource === "string" || resource instanceof String) {