Add Rectangle.Eq and Point.In. Fix Rectangle.Clip. It could return a non-canonical rectangle if its arguments did not overlap. e.g. Rect(0, 0, 10, 10).Clip(Rect(0, 20, 10, 30)) -> Rect(0, 20, 10, 10)
Add Rectangle.Eq and Point.In.
Fix Rectangle.Clip.
It could return a non-canonical rectangle if its arguments
did not overlap.
e.g. Rect(0, 0, 10, 10).Clip(Rect(0, 20, 10, 30)) -> Rect(0, 20, 10, 10)

R=rsc, r
CC=golang-dev, golang-dev
http://codereview.appspot.com/1290041

Committer: Rob Pike <4dc7c9ec434ed06502767136789763ec11d2c4b7@golang.org>

bryanxu/go-zh,d0f/go-zh,glycerine/jeaten-go-arrayof-structof,rflanagan/reginaldflanagan-project1,mhennings/marcohennings-go,d0f/go-zh,rflanagan/reginaldflanagan-project1,sanjosh/sanjos100-tipc,mhennings/marcohennings-go,glycerine/jeaten-go-arrayof-structof,bryanxu/go-zh,scirelli/scirelli-go,scirelli/scirelli-go,rflanagan/reginaldflanagan-project1,mhennings/marcohennings-go,sanjosh/sanjos100-tipc,webfd/go-zh,webfd/go-zh,sanjosh/sanjos100-tipc,glycerine/jeaten-go-arrayof-structof,rdp/rogerpack2005-golang,sanjosh/sanjos100-tipc,rdp/rogerpack2005-golang,rflanagan/reginaldflanagan-project1,Triskite/willstone-goclone,d0f/go-zh,sanjosh/sanjos100-tipc,rflanagan/reginaldflanagan-project1,d0f/go-zh,scirelli/scirelli-go,npe9/noahevans-go9,glycerine/jeaten-go-arrayof-structof,glycerine/jeaten-go-arrayof-structof,rdp/rogerpack2005-golang,npe9/noahevans-go9,npe9/noahevans-go9,webfd/go-zh,rflanagan/reginaldflanagan-project1,webfd/go-zh,npe9/noahevans-go9,webfd/go-zh,mhennings/marcohennings-go,bryanxu/go-zh,scirelli/scirelli-go,bryanxu/go-zh,mhennings/marcohennings-go,scirelli/scirelli-go,rdp/rogerpack2005-golang,d0f/go-zh,npe9/noahevans-go9,mhennings/marcohennings-go,bryanxu/go-zh,webfd/go-zh,glycerine/jeaten-go-arrayof-structof,d0f/go-zh,sanjosh/sanjos100-tipc,npe9/noahevans-go9,Triskite/willstone-goclone,d0f/go-zh,glycerine/jeaten-go-arrayof-structof,rdp/rogerpack2005-golang,scirelli/scirelli-go,scirelli/scirelli-go,rdp/rogerpack2005-golang,Triskite/willstone-goclone,mhennings/marcohennings-go,webfd/go-zh,bryanxu/go-zh,Triskite/willstone-goclone,npe9/noahevans-go9,Triskite/willstone-goclone,sanjosh/sanjos100-tipc,bryanxu/go-zh,rflanagan/reginaldflanagan-project1,mhennings/marcohennings-go,rdp/rogerpack2005-golang,Triskite/willstone-goclone,bryanxu/go-zh,Triskite/willstone-goclone,scirelli/scirelli-go,npe9/noahevans-go9,glycerine/jeaten-go-arrayof-structof,webfd/go-zh,Triskite/willstone-goclone,rdp/rogerpack2005-golang,sanjosh/sanjos100-tipc,rflanagan/reginaldflanagan-project1,d0f/go-zh