Declare package so that "go get" this repo doesn't complain.

package github.com/gyuho/goraph/...
        imports github.com/gyuho/goraph/algorithm/tsdfs
        imports github.com/gyuho/goraph/algorithm/tsdfs:
/usr/local/google/home/samschaevitz/gocode/src/github.com/gyuho/goraph/algorithm/tsdfs/tsdfs_test.go:26:4: expected 'package', found 'EOF'
Merge pull request #4 from samschaevitz/patch-3

Declare package so that "go get" this repo doesn't complain.