rename main test file so it is picked up by test_package
remove the old, somewhat duplicated tests in inst/tests/
add a test which runs the examples and checks there are no errors
add a custom label to examples tests which indicates which example failed.
stop R CMD check griping about too long lines in some examples.
Merge pull request #152 from gavinsimpson/fix-example-widths

stop R CMD check griping about too long lines in some examples.
Merge pull request #150 from gavinsimpson/test-examples

Test examples.  I'm merging with Caution :)
Building a more informative `print.download` method.  Closing out Issue #139.