131 Initial implementation of table balancing

[PeterJFB]

• textcomponent.rs:
  • Implements transform_table, which finds widths / heights of each cell based on some balancing formula, and splits any word which wrap within a cell.
  • Implements word_wrapping, returning a list where each entry fits within a single line
• markdown_renderer.rs Reimplements render_table, using widths / heights and clipping to determine how many rows in each cell should be rendered (otherwise the cell will not be rendered(?)).
• parser.rs and md.pest:
  • Add support of empty cells in parser
  • Fix link highlighting when they have no separation

Remaining work / considerations:

• unify use of word-wrapping in paragraph and table cells
  • add support for hyphen!
• more stress-testing
  • fix link highlighting when wrapping
  • extremely narrow overflowing column will not render bottom row
• find a way to keep Copy-trait on TextNode enum
  • Seeing that TextNode is part of TextComponent, which is already expensive to duplicate, i think is it a reasonable place to store the dynamically sized Table information, and improves some of the implicit handling of the meta_info struct (see content_as_lines and selected_heights).

[henriklovhaug]

Could you add a more gracious fail when the table gets too big to render?

[PeterJFB]

Could you add a more gracious fail when the table gets too big to render?

Updated balancing function to consider (relatively) large cells.
Added support for empty cells, which also used to panic.

[PeterJFB]

We're at a point where the implementation is relatively stable, it can be considered ready if nothing is added the next two days:)

[PeterJFB]

Remaining work has been addressed