* Consistent license message for all the go files
* Fixing the last set of unconsistencies with the license headers
* Addressing PR review comments
* Fixing busy.go and busy_test.go license header
Rename all files importing the "testing" package in "platform/model"
so that they only get compiled in test builds. This avoids the side
effects of the testing package (notably, defining some command line
flags with the "flags" package) for codebases importing the model
package.