Version 1.0.0-beta.1

**Note:** This changelog only provides basic information about the enormous
          changes introduced with Pico 1.0.0-beta.1. Please refer to the
          UGPRADE section of the docs for details.

```
* [Security] (9e2604a) Prevent content_dir breakouts using malicious URLs
* [New] Pico is on its way to its first stable release!
* [New] Provide pre-bundled releases
* [New] Heavily expanded documentation (inline code docs, user docs, dev docs)
* [New] New routing system using the QUERY_STRING method; Pico now works
        out-of-the-box with any webserver and without URL rewriting; use
        `%base_url%?sub/page` in markdown files and `{{ "sub/page"|link }}`
        in Twig templates to declare internal links
* [New] Brand new plugin system with dependencies (see `PicoPluginInterface`
        and `AbstractPicoPlugin`); if you're plugin dev, you really should
        take a look at the UPGRADE section of the docs!
* [New] Introducing the `PicoDeprecated` plugin to maintain full backward
        compatibility with Pico 0.9 and Pico 0.8
* [New] Support YAML-style meta header comments (`---`)
* [New] Various new placeholders to use in content files (e.g. `%site_title%`)
* [New] Provide access to all meta headers in content files (`%meta.*%`)
* [New] Provide access to meta headers in `$page` arrays (`$page['meta']`)
* [New] The file extension of content files is now configurable
* [New] Add `Pico::setConfig()` method to predefine config variables
* [New] Supporting per-directory `404.md` files
* [New] #103: Providing access to `sub.md` even when the `sub` directory
        exists, provided that there is no `sub/index.md`
* [New] #249: Support the `.twig` file extension for templates
* [New] #268, 269: Now using Travis CI; performing basic code tests and
        implementing an automatic release process
* [Changed] Complete code refactoring
* [Changed] Source code now follows PSR code styling
* [Changed] Replacing constants (e.g. `ROOT_DIR`) with constructor parameters
* [Changed] Paths (e.g. `content_dir`) are now relative to Pico's root dir
* [Changed] Adding `Pico::run()` method that performs Pico's processing and
            returns the rendered contents
* [Changed] Renaming all plugin events; adding some new events
* [Changed] `Pico_Plugin` is now the fully documented `DummyPlugin`
* [Changed] Meta data must start on the first line of the file now
* [Changed] Dropping the need to register meta headers for the convenience of
            users and pure (!) theme devs; plugin devs are still REQUIRED to
            register their meta headers during `onMetaHeaders`
* [Changed] Exclude inaccessible files from pages list
* [Changed] With alphabetical order, index files (e.g. `sub/index.md`) are
            now always placed before their sub pages (e.g. `sub/foo.md`)
* [Changed] Pico requires PHP >= 5.3.6 (due to `erusev/parsedown-extra`)
* [Changed] Pico now implicitly uses a existing `content` directory without
            the need to configure this in the `config/config.php` explicitly
* [Changed] Composer: Require a v0.7 release of `erusev/parsedown-extra`
* [Changed] #93, #158: Pico doesn't parse all content files anymore; moved to
            `PicoParsePagesContent` plugin, but still impacts performance;
            Note: This means `$page['content']` isn't available anymore, but
            usually the new `$page['raw_content']` is suitable as replacement.
* [Changed] #116: Parse meta headers using the Symfony YAML component
* [Changed] #244: Replace opendir() with scandir()
* [Changed] #246: Move `config.php` to `config/` directory
* [Changed] #253: Assume HTTPS if page is requested through port 443
* [Changed] A vast number of small improvements and changes...
* [Fixed] Sorting by date now uses timestamps and works as expected
* [Fixed] Fixing `$currentPage`, `$nextPage` and `$previousPage`
* [Fixed] #99: Support content filenames with spaces
* [Fixed] #140, #241: Use file paths as page identifiers rather than titles
* [Fixed] #248: Always set a timezone; adding `$config['timezone']` option
* [Fixed] A vast number of small bugs...
* [Removed] Removing the default Twig cache dir
* [Removed] Removing various empty `index.html` files
* [Removed] Moving Pico's excerpt feature to `PicoExcerpt` plugin
```