Kerning line fit

Find which lines of a text block are too wide once the font's kerning and ligatures are applied.

A font is described by a glyph table and a kerning list. Glyph entries look like "a=5": the character a is 5 units wide (the space is written " =3"). An entry whose key has two letters, such as "fi=7", is a ligature: those two letters, side by side, are drawn as one glyph of that width. A character that has no entry is default_width wide.

To measure a line:

1. Remove every space at the end of the line. Spaces at the start or in the middle stay and are measured like any other character.
2. Read the remaining text from left to right. At each position, if that character and the next one form a ligature, take them as a single glyph; otherwise take one character as a glyph. (So with ligatures fi and ff, the text ffi is the glyph ff followed by i.)
3. The line's width is the sum of its glyph widths plus the kerning adjustment for every pair of neighbouring glyphs. For a pair, the *left letter* is the last character of the left glyph and the *right letter* is the first character of the right glyph.

Kerning entries look like "AV=-3" (exact pair), "A*=-1" (any letter after A) or "*V=-2" (any letter before V); the pair may include a space. For a given pair of letters use the first rule that applies: the exact entry, otherwise the L* entry for the left letter, otherwise the *R entry for the right letter, otherwise 0. If the same entry key is listed more than once, the last one listed is the one that counts. Kerning never applies inside a ligature.

A line is overfull when its width is strictly greater than column_width.

Input: glyphs (list of strings), kerning (list of strings), default_width (integer), column_width (integer), lines (list of strings).

Output: a list with one [line_index, overflow] pair (0-based index, width - column_width) for every overfull line, ordered by overflow, largest first, and by line index, smallest first, when overflows are equal. Return [] if no line is overfull.