make additional tests optional

- Remove them from the MANIFEST as they are
  not supposed to be distributed.
detect other uname -m outputs

- x86_64, amd64 => MODEL:=64
- i386, i586, i686 => MODEL:32
Merge pull request #697 from MartinNowak/fixAutoMODEL

detect other uname -m outputs
Merge pull request #654 from MartinNowak/optionalTests

[2.065] make additional tests optional