Switch to new event system (#9)

* `SignalEvents` and `synchronized` mode for `EventsListenable`

* cascade syntax

* clean up

* `RoomEvents`

* `ParticipantEvents`

* all events implemented

* make it compile with M1 macs

* dispose logic

* cleaner connect logic

* ask to publish

* fix initial EngineTrackAddedEvent glitch

* fix unpublishTrack bug

* clean up

* better events docs

* organize event types

* clean up

* cleaner wait logic

* wait for event instead of using Completer

* notifyListeners

example/ios/Runner.xcodeproj/project.pbxproj

@@ -331,6 +331,7 @@
 				DEBUG_INFORMATION_FORMAT = "dwarf-with-dsym";
 				ENABLE_NS_ASSERTIONS = NO;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
+				EXCLUDED_ARCHS = "";
 				GCC_C_LANGUAGE_STANDARD = gnu99;
 				GCC_NO_COMMON_BLOCKS = YES;
 				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
@@ -342,7 +343,6 @@
 				IPHONEOS_DEPLOYMENT_TARGET = 12.1;
 				MTL_ENABLE_DEBUG_INFO = NO;
 				SDKROOT = iphoneos;
-				SUPPORTED_PLATFORMS = iphoneos;
 				TARGETED_DEVICE_FAMILY = "1,2";
 				VALIDATE_PRODUCT = YES;
 			};
@@ -406,6 +406,7 @@
 				DEBUG_INFORMATION_FORMAT = dwarf;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
 				ENABLE_TESTABILITY = YES;
+				EXCLUDED_ARCHS = "";
 				GCC_C_LANGUAGE_STANDARD = gnu99;
 				GCC_DYNAMIC_NO_PIC = NO;
 				GCC_NO_COMMON_BLOCKS = YES;
@@ -461,6 +462,7 @@
 				DEBUG_INFORMATION_FORMAT = "dwarf-with-dsym";
 				ENABLE_NS_ASSERTIONS = NO;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
+				EXCLUDED_ARCHS = "";
 				GCC_C_LANGUAGE_STANDARD = gnu99;
 				GCC_NO_COMMON_BLOCKS = YES;
 				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
@@ -472,7 +474,6 @@
 				IPHONEOS_DEPLOYMENT_TARGET = 12.1;
 				MTL_ENABLE_DEBUG_INFO = NO;
 				SDKROOT = iphoneos;
-				SUPPORTED_PLATFORMS = iphoneos;
 				SWIFT_COMPILATION_MODE = wholemodule;
 				SWIFT_OPTIMIZATION_LEVEL = "-O";
 				TARGETED_DEVICE_FAMILY = "1,2";