Version 1.0.0-beta.2

```
* [New] Introducing the `PicoTwigExtension` Twig extension
* [New] New `markdown` filter for Twig to parse markdown strings; Note: If you
        want to parse the contents of a page, use the `content` filter instead
* [New] New `sort_by` filter to sort an array by a specified key or key path
* [New] New `map` filter to get the values of the given key or key path
* [New] Introducing `index.php.dist` (used for pre-bundled releases)
* [New] Use PHP_CodeSniffer to auto-check source code (see `.phpcs.xml`)
* [New] Use Travis CI to generate phpDocs class docs automatically
* [Changed] Improve documentation
* [Changed] Improve table styling in default theme
* [Changed] Update composer version constraints; almost all dependencies will
            have pending updates, run `composer update`
* [Changed] Throw a RuntimeException when the `content` dir isn't accessible
* [Changed] Reuse `ParsedownExtra` object; new `onParsedownRegistration` event
* [Changed] `$config['rewrite_url']` is now always available
* [Changed] `DummyPlugin` class is now final
* [Changed] Remove `.git` dirs from `vendor/` when deploying
* [Changed] Various small improvements and changes...
* [Fixed] `PicoDeprecated`: Sanitize `content_dir` and `base_url` options when
          reading `config.php` in Picos root dir
* [Fixed] Replace `urldecode()` (deprecated RFC 1738) with `rawurldecode()`
          (RFC 3986) in `Page::evaluateRequestUrl()`
* [Fixed] #272: Encode URLs using `rawurlencode()` in `Pico::getPageUrl()`
* [Fixed] #274: Prevent double slashes in `base_url`
* [Fixed] #285: Make `index.php` work when installed as a composer dependency
* [Fixed] #291: Force `Pico::$requestUrl` to have no leading/trailing slash
```