* Lossless image optimization (using ImageOptim).
This shouldn't change the visual appearance of any images. ImageOptim
was run with the highest compression setting except that JPEG metadata
stripping was disabled because some users prefer to avoid stripping
JPEG metadata.
* Update READMEs that have Changelogs for themes impacted by lossless image optmization change.
* Removed unused template
* Added missing image asset for home template
* Removed unused color
* Tightened up 404 pattern layout (elimiated empty space)
* Removed unnecessary color assignments (foreground set to foreground, background set to background)
* Converted 'primary' colors (not supplied by theme) to use 'foreground' instead
