@AndroidParcelable to check before adding blank constructor

[tobykurien]

Currently it forcefully adds a blank constructor and doesn't allow you to add your own

[Buggaboo]

I tried fixing this today, but for some reason, the compiler does not acknowledge the empty ctors that were generated by the AndroidParcelable active annotation.

You may wanna have a go at it.

I don't know if it's a bug. We could throw an error if the user doesn't explicitly provide one.

[tobykurien]

Not sure if we're missing each other - what I meant by this issue is
that if I create a bean and add an empty constructor, then add the
@AndroidParcelable annotation, I get a compile error because there
are now 2 empty constructors. If @AndroidParcelable first checked
that the empty c'tor exists, then it can bypass adding it's own, and
hence no compile error :-)