sys: elfloader implementation for RIOT

The elfloader implementation was created for the Telematik-Softwareproject SS14.
I think I couldn't bring my point along.
But I guess we can agree on:
• to many line breaks which don't help readability.
• we can use up to 100 characters if it improve readability compared to 80 characters and a line break.
• use 4 spaces instead of tab characters