Major sdram video memory release

Zeus,

I could not get things stable enough to do a release with advanced pic, post, sdram video and board top level cleanup. So, I started all over with just the basics. Later, over time I will submit smaller changes and additions as I work through stability issues.

This release is still considered a major release. It includes many top level architectural changes needed to support video modes placed into sdram.

The following additions were made:
Video subsystem placed into 100Mhz domain
Removed unused 25Mhz pll clock
Added top level fml arbitrer
Re-mapped sdram memory space
CPU read/write requests to video memory redirected to sdram
VGA subsystem read/write requests to video memory redirected to sdram
Pipelined video modes to take advantage of fml burst transfers
Added fifo logic to video subsystem to support fml burst transfers
All references to previous sram video memory has been removed

All supported boards de0, de1, de2 and de2-115 use sdram for video memory. All these supported boards compile and should run all standard programs(ms-dos, windows 3.0, edit, gods, etc...) right out of the box.

Please review and consider merging this pull request into the official master branch and making a official release.

Thanks!

Charley Picker otherwise known as sir chuckalot