Add a new `preserveExecutionOrder` option

[kl0tl]

According to this article, setting the async property of dynamically created scripts to false let the browser download them in parallel (unlike $script.order) but preserve the execution order. The difference is mostly visible on mobile devices with slow connection.

Is there any drawbacks of this approach ?

[rstacruz]

This needs to be applied to the src/ file, not the dist/ file.

[kl0tl]

@rstacruz Yes I’ve modified src/script.js :)