LDFLAGS: libtool: Use -release with unstable 0.9 releases

The rationale behind the switch (`-version-info' to `-release'):

* The 0.9 series is currently under development, and will gradually
  mature as the next stable (1.0), replacing the 0.4 series completely

* The series may still see:
  - ABI and API breakages with the earlier 0.9 versions
  - Feature additions and/or removals

Instead of bumping the `-version-info C+1:R:A' everytime something
breaks the backward-compatibility with the earlier 0.9 releases, we will
use the `-release RELEASE'. Once 0.9 graduates as the next stable (1.0),
we can switch back to using the `-version-info'.

Downside:

  * Every release of the package will not be binary compatible with any
    other release (which would frequently be the case anyway)

  * Applications that depend on (this) libquvi 0.9 release will have to
    be recompiled later again to use a new release of libquvi

Other:
* Leave the -version-info line commented out for the next stable (1.0)

Signed-off-by: Toni Gundogdu <legatvs@gmail.com>