Added Contracts project, for sharing geographic co-ordinate location objects...

(at some point we will probably have to upload/export these to somewhere, right?)
#3 moved 'Contracts' to 'Mono.Contracts'. Ran into some issues with unit testing android class lib in VS
#3 - Got rid of TextFileRepository, and made it generic so it's no longer a text-specific type of repository
#3 started using a DTO for location based data, instead of just a formatted string...

Still need to properly implement a mapping resolver - perhaps convention-based to determine whether an object can be properly mapped to a string representation of itself. It's either that or serialise it to JSON or something.
Merge pull request #5 from wislon/#3_location_object

#3 location object fixes (merged)