Update various comments and variable names to make golint happy.

Previously there were around a few dozen items it complained about; this eliminates all of those issues.

$ GOPATH/bin/golint . | wc -l
       0
$ go test
PASS
ok      apns    0.013s
Add a legacy file and tests to avoid annoying breaking changes.

Lately a legitimate number of package managers for Go have cropped up, but this lib came into existence when the options were a little more sparse (i.e. "breaking public API change? Fork the repo!")

This supports #11 and keeps the identifiers around but outside of the normal code...for now. I'll probably wind up forking eventually, but we'll see if we can be creative in the meantime.

$ $GOPATH/bin/golint .
legacy.go:10:2: don't use ALL_CAPS in Go names; use CamelCase
legacy.go:11:2: don't use ALL_CAPS in Go names; use CamelCase
legacy.go:12:2: don't use ALL_CAPS in Go names; use CamelCase
legacy.go:13:2: don't use ALL_CAPS in Go names; use CamelCase
legacy.go:14:2: don't use ALL_CAPS in Go names; use CamelCase
legacy.go:15:2: don't use ALL_CAPS in Go names; use CamelCase

$ go test
PASS
ok      apns    0.013s
Update the de-linted code to include the fix from #12
Merge pull request #13 from anachronistic/legacy-interface

Legacy interface