Implement new unit structure

[baetheus]

Standardize default unit structure, each needs a suffix and a value:

Pixel

suffix: none
values: 0, 1, 2, 4, 8, 16, 32, 64, 128

View Height

suffixes: vh
values: 100

Percentages

suffix: p
values: 10, 20, 25, 30, 33, 40, 50, 60, 66, 70, 75, 80, 90, 100

Vertical Rhythm

suffix: cr
values: 1, 2, 3, 4

Character

suffix: ch
values: 25, 50, 75, 100