Update TravisCI to goclean script.

- Also update to use the new container-based builds
- Modify the tests slightly to make golint happy

.travis.yml

@@ -2,12 +2,17 @@ language: go
 go:
   - release
   - tip
+sudo: false
+before_install:
+  - gocleandeps=c16c849abae90c23419d
+  - git clone https://gist.github.com/$gocleandeps.git
+  - goclean=71d0380287747d956a26
+  - git clone https://gist.github.com/$goclean.git
 install:
   - go get -d -t -v ./...
-  - go get -v golang.org/x/tools/cmd/cover
+  - bash $gocleandeps/gocleandeps.sh
 script:
-  - go test -v -covermode=count -coverprofile=profile.cov
-after_success:
-  - go get -v github.com/mattn/goveralls
   - export PATH=$PATH:$HOME/gopath/bin
+  - bash $goclean/goclean.sh
+after_success:
   - goveralls -coverprofile=profile.cov -service=travis-ci

internal_test.go

@@ -129,10 +129,16 @@ func TstWriteBlockHeader(w io.Writer, pver uint32, bh *BlockHeader) error {
 	return writeBlockHeader(w, pver, bh)
 }
 
+// TstMessageHeader is simply a redefinition of the internal messageHeader that
+// is used to make golint happy since it rightly complains that it's typically
+// not a good idea to return unexported types.
+type TstMessageHeader messageHeader
+
 // TstReadMessageHeader makes the internal readMessageHeader function available
 // to the test package.
-func TstReadMessageHeader(r io.Reader) (int, *messageHeader, error) {
-	return readMessageHeader(r)
+func TstReadMessageHeader(r io.Reader) (int, *TstMessageHeader, error) {
+	n, hdr, err := readMessageHeader(r)
+	return n, (*TstMessageHeader)(hdr), err
 }
 
 // TstReadOutPoint makes the internal readOutPoint function available to the