Move LICENSE, AUTHORS, PATENTS into the dart directory.

dart/PATENTS

 Additional IP Rights Grant (Patents)
 
 "This implementation" means the copyrightable works distributed by
 Google as part of the Dart Project.
 
 Google hereby grants to you a perpetual, worldwide, non-exclusive,
 no-charge, royalty-free, irrevocable (except as stated in this
 section) patent license to make, have made, use, offer to sell, sell,
 import, transfer, and otherwise run, modify and propagate the contents
 of this implementation of Dart, where such license applies only to
 those patent claims, both currently owned by Google and acquired in
 the future, licensable by Google that are necessarily infringed by
 this implementation of Dart. This grant does not include claims that
 would be infringed only as a consequence of further modification of
 this implementation. If you or your agent or exclusive licensee
 institute or order or agree to the institution of patent litigation
 against any entity (including a cross-claim or counterclaim in a
 lawsuit) alleging that this implementation of Dart or any code
 incorporated within this implementation of Dart constitutes direct or
 contributory patent infringement, or inducement of patent
 infringement, then any patent rights granted to you under this License
 for this implementation of Dart shall terminate as of the date such
 litigation is filed.