Fix HappyFoxGear init method declaration

Appears the method declaration was copied/pasted from header file.

Fixes:

(lldb) Objective-C stub for message `initWithInstanceUrl:apiKey:authoCode:priorityID:categoryID:' type `@@:@@@@@' not precompiled. Make sure you properly link with the framework or library that defines this message.
Merge pull request #12 from interhive/patch-1

Fix HappyFoxGear init method declaration