Started building unit tests based on `testthat` using @cboettig's tests for `rfigshare` as an example.  Simple stuff for now.

Also started changing text output in functions from either `cat` or `writeLines` to `message` to help facilitate testing using `expect_message`.
Building more tests and doing some minor fixes where the tests were failing :)
Added some more tests.  Fixed the roxygenize error for get_chroncontrol.  Things should work nicely now.
Merge pull request #72 from SimonGoring/master

Multiple changes, mostly centered around building tests for the package.