MFC r330116, r330118, r330251, r330254

r330116:
Some missing LOADER_EFI build option descriptions

r330118:
Add missing punctuation to *_LOADER_EFI descriptions...

r330251:
Remove LOADER_EFI description files

LOADER_EFI functionality got folded into EFI as of r330248.

r330254:
Add descriptions for recently added loader options