Add inline Blade support to Markdown

[caendesilva]

Introduction

Since HydePHP makes heavy use of Markdown there are some extra features and helpers
created just for Hyde to make using Markdown even easier!

Fixes #463

Blade Support

Since Hyde v0.30.x you can use Laravel Blade in Markdown files!

Using Blade in Markdown

To use Blade in your Markdown files, simply use the Blade shortcode directive,
followed by your desired Blade string.

Standard syntax

 [Blade]: {{ "Hello World!" }} // Will render: 'Hello World!'

Blade includes

Only single-line shortcode directives are supported. If you need to use multi-line Blade code,
use an @include directive to render a more complex Blade template.
You can pass data to includes by specifying an array to the second argument.

 [Blade]: @include("hello-world")
 [Blade]: @include("hello", ["name" => "World"])

Enabling Blade-supported Markdown

It's disabled by default since it allows arbitrary PHP to run, which could be a security risk,
depending on your setup. However, if your Markdown is trusted, and you know it's safe,
you can enable it in the config/markdown.php file.

// torchlight! {"lineNumbers": false}
'enable_blade' => true,

Limitations

All shortcodes must be the first word on a new line.
For example, using a space before the [Blade]: will intentionally cause it to not render.