Feature: build life cycle callbacks (prehtml, prepdf, etc)

[bmcminn]

I tend to use C style inline comments (// comment here) in my markdown files because:

• my editor theme grays out <!-- html --> comments making them hard to read/see
• I like being able to use // TODO: ... and // NOTE: ... as specific notes to myself for future review

It would be helpful if I could register a standard event hook callback in my ibis.php that BuildCommand.php issues before converting a file to HTML from markdown.

I have a working proof of concept in my own fork of the repo that introduces a prehtml() global function that one can optionally provide in their ibis.php if they want to preprocess their markdown content for whatever reason.

[themsaid]

That's a nice idea. Can you open a Pull Request?

[bmcminn]

Working on a PR right now