Web: fix column headings that lack gradients

Web: fix column headings that lack gradients

On the following two webpages there are 
headings that are solid colors rather than
gradients, and this looks broken. 
  introduction/freedom
  download

This patch adds two CSS classes for this 
kind of heading, and removes the classes 
that create solid color headings.

Includes three commits:

Web: use column-center-middle- CSS classes
use column-center-middle-color2 and
column-center-middle-color3 instead of
div.color2, div.color3, etc.

Web: CSS: add column-center-middle classes
add column-center-middle-color2
add column-center-middle-color3
remove div.color1 .color2 .color3 .color4

Web: CSS: put column h3 headers together

[pwm, 2015-02-11 18:55:06]

Please review, thanks.

[pkx166h, 2015-02-17 13:21:15]

Patch on countdown for Feb 19th

[pkx166h, 2015-02-19 10:55:55]

Patch counted down - please push (you can give me a git formatted patch as
normal of you like)

[pkx166h, 2015-02-19 15:32:41]

author	Paul Morris <paulwmorris@gmail.com>	
	Wed, 11 Feb 2015 17:08:34 +0000 (12:08 -0500)
committer	James Lowe <pkx166h@gmail.com>	
	Thu, 19 Feb 2015 15:30:44 +0000 (15:30 +0000)
commit	d41686f992941f8fa8c567b6c1643d5dd4de17fc