Rewrite (#42)

**New Features**
* Supports TypeScript out of the box
* Supports `import` syntax out of the box
* Better assert failure messages
* Stack traces point to the line in readme with the failing assert
* exits with code 1 when no tests found

**BREAKING CHANGES**
* Dropped support for Node < 8
* Code blocks must be tagged with `test`, see readme for examples.
  To get the old behavior add `--auto` argument
* Does not read babelrc file by default. Add `--babel` flag to enable it.

.travis.yml

@@ -1,6 +1,4 @@
 language: node_js
-before_script:
-  - "npm run lint"
 node_js:
   - "10"
   - "8"

examples/auto-discover-tests/index.js

@@ -0,0 +1 @@
+module.exports = num => Math.pow(num, 2);

examples/auto-discover-tests/package.json

@@ -0,0 +1,13 @@
+{
+  "private": true,
+  "name": "@laat/auto",
+  "version": "1.0.0",
+  "main": "index.js",
+  "license": "MIT",
+  "scripts": {
+    "test": "readme-assert --auto"
+  },
+  "devDependencies": {
+    "readme-assert": "^5.0.6"
+  }
+}

examples/auto-discover-tests/readme.md

@@ -0,0 +1,37 @@
+# auto discover test blocks
+
+The default behavior is to detect code blocks tagged with `test`:
+
+````
+```js test
+1 + 1 // => 1
+```
+````
+
+We can also try to infer the tests to run with the `--auto` flag, which tries tries to find magic comments `//=>` in the documentation.
+
+````
+```js
+1 + 1 // => 1
+```
+````
+
+### Command
+
+```
+readme-assert --auto
+```
+
+````
+```js
+const pow2 = require("@laat/auto");
+pow2(2); //=> 4
+pow2(4); //=> 16
+```
+````
+
+```js
+const pow2 = require("@laat/auto");
+pow2(2); //=> 4
+pow2(4); //=> 16
+```