improve handling of malformed data
fixes #45
Simplified tests:

 - using known UNIX timestamps to remove regexps and make assertions clearer
 - removed extra testing/dependency on parseMessage() in mean/% tests
Merge pull request #46 from JamesCohen-awin/issue-45

improve handling of malformed data
Merge pull request #47 from JamesCohen-awin/test-tidyup

Simplified tests