Integrate FlexBox layout

Integrate flexbox CSS property parsing.

Implement utils for computing flexbox-relevant sizes.

Adjust flexbox terminology

Parse FlexBox CSS properties, draft alignment code.

Draft flexbox layout

Fix release of CatTrap 0.4 (as I should've called it...)

Test table lowering

Bridge rowspan/colspan from HTML to CSS via useragent stylesheet.

Support colspan on column elements.

Parse & apply CSS <table>-styling properties.

Allow styling table columns & rows!

Implement table layout.

Implement basic table layout.

Implement more of <table> layout

Expose text data from main module.

Improve concurrency, release 0.3, & (not in 0.3) better expose text info

Give up on addressing all memory leaks.

Upload missing files.

Segfault/performance fixes.