rename of test programs

[Brian Gough]

I have been changing the executable names of the test programs in the
Makefiles to be 'test' consistently, so that it is possible to check
that the tests link correctly without having to run make
check. Otherwise there does not seem to be any way to build the tests
without running them, and that takes ages.

Anyway, this may lead to some stale files with the original names next
time you build the library.