Move WritableRepository methods to Repository interface?

[Dain Sundstrom]

I was applying GERONIMO-1227 from Toby and it occurred to me that we  
may want to simply merge WritableRepository into the Repository  
interface and add a "boolean canWrite()" method to the interface.   
Then the console could just scan for all repositories and allow the  
user a choice of which writable one to upload to.

What do you think?
BTW this would be for 1.1.

-dain