A few changes to tests and code

- move the easy pkg test to easy_test.go
- use gocheck directly rather than through gopkg.in
- use a switch in place of chained ifs in gotxs.go
```
[1] % go get github.com/go-check/check
# github.com/go-check/check
../../go-check/check/error.go:4: "ERROR: the correct import path is gopkg.in/check.v1 ... " evaluated but not used
```