Initval fixes.

* Allow 2x int8 initvals for hash64_string
* Add missing SQL functions for hash128 with initvals
Bump extension version to 1.1
pgsql86: use IV from io[0].

IV usage was missing, add.
New hash: SipHash-2-4

Secure and fast 64-bit hash for short strings.
makefile target for tarball.
Bump debian ver to 1.1