write some helper tests

I decided to use MiniTest since I've never used it before and wanted to
experience a different testing framework than Rspec. To make the full
leap I'm also goijg straight into assertion style tests. `rake test` to
run them.

I moved the helpers out to their own module to make testing them a lot
easier.
use minitest-reporter for color output
make some tests for blog posts

I tried to make these tests as generic as possible. there isn't a whole
lot that needs to be tested about a blog post other than that it parses
information correctly, but that's very implementation specific.

I've also moves some shared test logic into test_helper.rb (not to be
confused with helper_test.rb)
test all of the routes

this is just a basic sweep to assure that each of routes is working. if
I manage to introduce an error anywhere then the page should fail. I'm
not too concerned about individual tests for each page, though I plan on
writing a few special conditions down the line.
reorganize and test latest_posts

I've moved latest_posts into the SiteHelpers module since it's small
enough that I don't feel it's cluttered and it makes it easier to test.
the test itself is rather complicated but it ensures that a random set
of posts are created that don't match my specific criteria, so it should
never give a flase positive result.
move css3_animations helper to SiteHelpers for consistency