Fix debian packaging

Fixed various problems, the worst of which were:
* hubo-ach's header files were included in both the hubo-ach and hubo-ach-dev packages, causing a collision that made both unusable
* The hubo-ach-dev package did not depend on the hubo-ach package, which could lead to weirdness if only the -dev package were installed
* la files [must be excluded](http://wiki.debian.org/ReleaseGoals/LAFileRemoval) from debian packages unless absolutely necessary
* The postinst script [must](http://www.debian.org/doc/debian-policy/ch-sharedlibs.html#s-ldconfig) call ldconfig