fix build break when atomspace is not being built

It can happen that atomspace is not built ...
Fix build breaks if python is not installed.

Yes, it can happen ...
Hush non-standard error message.
Fix build break that obtains with gcc-4.7, 4.8
Fix compiler warning
Remove some crazy library dependencies
Merge pull request #1081 from linas/die

fix assorted build breaks that new users might trip over.