Doc Tests

Lazytest can run tests in code blocks of your markdown files with --md FILE. It looks for any triple backtic-delimited code block that has clojure or clj as the language specifier, and that doesn't have lazytest/skip=true in the info-string, bundles it into a standalone describe block, and then runs all of the suites as a single suite under the name of the markdown file.

It determines what should be considered a test ((expect (= x y))) by the presence of =>. Code immediately before a line containing => (leading ; optional) is treated as the actual, and the value after treated as the expected result.

This will run:

```clojure
(defn adder [a b]
  (+ a b))

(adder 5 6)
;; => 11
```

Whereas these will not (first is skipped, second isn't "clojure" or "clj"):

```clojure lazytest/skip=true
(System/exit 1)
;; => exit!!!
```

```clojurescript
print("Hello world!")
```

Additionally, a custom string can be used instead of the default (headers from the markdown file) by using the info-string lazytest/describe:

```clojure lazytest/describe=easy-adder
(+ 5 6)
;; => 11
```

will be printed as:

  readme-md
    easy-adder
      √ Doc Tests