Stream_memspeed

This is a benchmark program that tests the memory bandwidth for a variety of
operations. It is an Amiga OS 4.0 port of stream_memspeed by Gunnar von Boehn.
The original can be found at http://www.greyhound-data.com/gunnar/glibc/.

The source-code is provided.

This version fixes the following bugs:
- Memory bandwidth calculation was wrong, causing it to inflate the numbers
- Some parts took 1 MB to be 1000000 (like the original). Everything now uses 1
MB = 1048576 bytes
- It now checks if memory allocation succeeded, and drops to a smaller sized
buffer if you don't have enough memory free for 160 MB (which is the default)
- Reinserted the clock granularity check