remove some now-unused variables
rearrange so that most of the server code can be linked without main.c

Move global variables and one function out of main.c so that the rest of
the server can be linked with a test harness.
Test the low-level code in uloc.c

Also, tweak the debian build infrastructure so that we can pass
in arbitrary CFLAGS.

New program test_server that links with the non-main.c parts of
the server.  Currently only (as above) tests the low-level bits
of uloc.c.
rototill uloc.c to be a little less pathological

Notably, use realloc rather than allocating and copying a whole new
table.

Also be more consistent about operating in terms of array indices rather
then pointers.