Grids IE8 SCSS: Fixed left padding issue in dual icon scenarios (in which only external icons will appear).
Fixes gh-3285.
Demos: Fixed various broken links.
Merge pull request #3892 from EricDunsworth/v3.0-broken-link-fixes

Demos: Fixed various broken links.
Gitignore: Added sprite naming patterns from v4.0's version of this file.
Prevents generated sprite files from appearing as unversioned in non-v4.0 branches.
Merge pull request #3894 from EricDunsworth/v3.0-gitignore-sprite

Gitignore: Added sprite naming patterns from v4.0's version of this file.
Merge pull request #3890 from EricDunsworth/v3.0-grids-icon-combos-ie8

Grids IE8 SCSS: Fixed left padding issue in dual icon scenarios (in whic...
Resolved merge conflict