Fix validation errors.

Also, add image dimensions and break long lines.
Reindent style.css.
Losslessly compress PNG files.

img/git-logo.png     | Bin 3668 -> 2758 bytes
img/msysgit-logo.png | Bin 8282 -> 6441 bytes

Total difference: -2751 bytes.
Use only Bootstrap components that are needed.

Add bootstrap-info.md with all the info.

Also, the layout is responsive now.
Add meta charset.