Value of REQUEST_CODE_OAUTH on EvernoteSession needs to be <= 0xffff.

The value of the ```REQUEST_CODE_OAUTH``` constant on the ```EvernoteSession``` class, needs to be changed to a value that's less than 0xffff to allow for compatibility with the ```FragmentActivity``` class on Android's support library.

**Background:**
The Support Library v4 implements a ```FragmentActivity``` class that is used when an activity needs to use the support versions of the Fragment and Loader APIs. The issue is that the ```startActivityForResult(...)``` method on that class has a limitation where the passed requestCode can't be greater than 0xffff (see [here](http://bit.ly/UF7k0J))

Since the value of ```REQUEST_CODE_OAUTH``` is currently higher than the specified limit, if an app sends a ```FragmentActivity``` as the Context parameter to the ```authenticate``` method of  ```EvernoteSession```, it will result in an ```IllegalArgumentException``` when that method tries to call ```startActivityForResult(...)``` passing ```REQUEST_CODE_OAUTH``` as the requestCode parameter.

A sample LogCat of the error can be seen [here](https://www.evernote.com/shard/s192/sh/0f979fda-efb0-4d04-9be4-995cd4bb92b9/0f6c3d05a6282de85a988c7180b2b272).