lib: Make VERSION macros agree with soname version

lib: Make VERSION macros agree with soname version

We have two distinct "library version" numbers: the soname version and
the version macros.  We need both for different reasons: the version
macros enable easy compile-time version detection (and conditional
compilation), while the soname version enables runtime version
detection (which includes the version checking done by things like the
Python bindings).

However, currently, these two version numbers are different, which is
unnecessary and can lead to confusion (especially in things like
Debian, which include the soname version in the package name).  This
patch makes them the same by bumping the version macros up to agree
with the soname version.

(We should probably keep the version number in just one place so they
can't get out of sync, but that can be done in another patch.)