Fix: Support empty style attribute (#296)
Fix: Support empty style attribute (#296)

Fixes a bug in which empty style attributes result in
unrecoverable JSX failures. For example:

```html
<div style>Foo</div>
```

Would result in the following console error:

```
Uncaught Invariant Violation: The `style` prop expects a
mapping from style properties to values, not a string.
For example, style={{marginRight: spacing + 'em'}} when
using JSX.
```

and the React JSX failing to render.

The problem is that empty properties are rendered as
boolean `true` by default. This is consistent with
HTML/React syntax interop expectations for most properties
but not `style`, which expects an `Object` value in
React-land.

Since an empty `style` attribute is semantically
meaningless (where HTML is concerned) we can simply skip
over this property.
yaycmyk/markdown-to-jsx,yaycmyk/markdown-to-jsx,probablyup/markdown-to-jsx,probablyup/markdown-to-jsx