Move the source files from src/ to src/gearman/.

--HG--
rename : src/Makefile => src/gearman/Makefile
rename : src/client.go => src/gearman/client.go
rename : src/client/job.go => src/gearman/client/job.go
rename : src/client_test.go => src/gearman/client_test.go
rename : src/gearman.go => src/gearman/gearman.go
rename : src/worker.go => src/gearman/worker.go
rename : src/worker/job.go => src/gearman/worker/job.go
rename : src/worker/jobclient.go => src/gearman/worker/jobclient.go
rename : src/worker_test.go => src/gearman/worker_test.go