EIB Interfacebus Description

I added the EIB page, which has a very brief description of the Element Interconnect Bus. The EIB interface is a internal IC bus used to connect functions within a Cell processor. Links were added to that new page from the IC Buses page, and the Buses by letter page; 'E' buses.

Also added a few new acronyms, the letter 'E' pages were updated:
Abbreviations and Acronyms, Ea,
Abbreviations and Acronyms, Eme,
Abbreviations and Acronyms, Ep,