two small improvements

I continue to fine-tune autoUnit for best results in all situations.
Also, I changed the platform to show the result from unix uname if available. This allows my Raspberry Pi to show 'armv6l' instead of '32-bit' (Issue #220)
However, it will also change linux PCs from '64-bit' to 'x86_64', and the same for 32 bit.
This does not bother me, but I can see how it might be 'uglier' to some.
If it is not acceptable I can change the code to return '32-bit' and '64-bit' for i386 and x86_64