v5 Class Name consistency, font sizes

[bnjmnrsh]

As per v5 request(s):

tachyons-css/tachyons#211 (comment)
PR: tachyons-css/tachyons#636

Expanded type scale for font-size, with self-consistent naming and an additional font size (4rem):

Class names	font-size value	Previous class names
fs1	.75rem	f7
fs2	.875rem	f6
fs3	1rem	f5
fs4	1.25rem	f4
fs5	1.5rem	f3
fs6	2.25rem	f2
fs7	3rem	f1
fs8	4rem	(None)
fs9, fs-subheadline	5rem	f-5, f-subheadline
fs10, fs-headline	6rem	f-6, f-headline

Thus, in new class names, the prefix fs is for font-size and fstyle is for font-style The new classes all have different names from Tachyons v4 classes, so they would not conflict with existing code.

Proposed changes submitted as a PR.

tachyons-css/tachyons#211 (comment)

Expanded type scale for font-size, with self-consistent naming and an additional font size (4rem):

Class names font-size value Previous class names
fs1 .75rem f7
fs2 .875rem f6
fs3 1rem f5
fs4 1.25rem f4
fs5 1.5rem f3
fs6 2.25rem f2
fs7 3rem f1
fs8 4rem (None)
fs9, fs-subheadline 5rem f-5, f-subheadline
fs10, fs-headline 6rem f-6, f-headline
Expanded scale for font-weight, with self-consistent naming and an additional font weight (1000):

Class name font-weight value Previous class name
fw-100 100 fw1
fw-200 200 fw2
fw-300 300 fw3
fw-400 400 fw4
fw-500 500 fw5
fw-600 600 fw6
fw-700 700 fw7
fw-800 800 fw8
fw-900 900 fw9
fw-1000 1000 (None)
New names for font-weight classes:

Class names font-weight value Previous class name
b, fw-bold bold b
fw-normal normal normal
And finally, new names for font-style classes:

Class names font-style value Previous class name
i, fstyle-italic italic i
fstyle-normal normal fs-normal
Thus, in new class names, the prefix fs is for font-size and fstyle is for font-style.

The new classes all have different names from Tachyons v4 classes, so they would not conflict with existing code.

PR: tachyons-css/tachyons#636