Add typescript support (davide-scalzo#177)

Author: jakebloom

index.d.ts

@@ -0,0 +1,72 @@
+declare module 'react-native-mixpanel' {
+  export class MixpanelInstance {
+    constructor(apiToken?: string)
+
+    initialize(): Promise<void>
+    getDistinctId(): Promise<string>  
+    getSuperProperty(propertyName: string): Promise<any>
+    track(event: string, properties?: Object): Promise<void>
+    flush(): Promise<void>
+    disableIpAddressGeolocalization(): Promise<void>
+    alias(alias: string): Promise<void>
+    identify(userId: string): Promise<void>  
+    timeEvent(event: string): Promise<void>
+    registerSuperProperties(properties: Object): Promise<void>
+    registerSuperPropertiesOnce(properties: Object): Promise<void>
+    initPushHandling(token: string): Promise<void>
+    set(properties: Object): Promise<void>
+    setOnce(properties: Object): Promise<void>
+    trackCharge(charge: number): Promise<void>
+    trackChargeWithProperties(charge: number, properties: Object): Promise<void>
+    increment(property: string, by: number): Promise<void>
+    union(name: string, properties: any[]): Promise<void>
+    removePushDeviceToken(deviceToken: Object): Promise<void>
+    removeAllPushDeviceTokens(): Promise<void>
+    addPushDeviceToken(token: string): Promise<void>
+
+    // android only
+    setPushRegistrationId(token: string): Promise<void>
+  
+    // android only
+    clearPushRegistrationId(): Promise<void>
+
+    reset(): Promise<void>
+  }
+
+  interface MixpanelAPI {
+    sharedInstanceWithToken(apiToken: string): Promise<void>;
+    getDistinctId(callback: (id?: string) => void): void;
+    getSuperProperty(propertyName: string, callback: (value: any) => void): void;
+    track(event: string): void;
+    trackWithProperties(event: string, properties: Object): void;
+    flush(): void;
+    disableIpAddressGeolocalization(): void;
+    createAlias(alias: string): void;
+    identify(userId: string): void;
+    timeEvent(event: string): void;
+    registerSuperProperties(properties: Object): void;
+    registerSuperPropertiesOnce(properties: Object): void;
+    initPushHandling(token: string): void;
+    set(properties: Object): void;
+    setOnce(properties: Object): void;
+    removePushDeviceToken(deviceToken: Object): void;
+    removeAllPushDeviceTokens(): void;
+    trackCharge(charge: number): void;
+    trackChargeWithProperties(charge: number, properties: Object): void;
+    increment(property: string, by: number): void;
+    union(name: string, properties: any[]): void;
+    addPushDeviceToken(token: string): void;
+  
+    // android only
+    setPushRegistrationId(token: string): void;
+  
+    // android only
+    clearPushRegistrationId(): void;
+
+    reset(): void;
+  }
+
+  const mixpanelApi: MixpanelAPI;
+  export default mixpanelApi;
+  
+}