fix uvarint helper: sqlite uvarints are big-endian

[zellyn]

The existing code uses encoding/binary's Uvarint function, which mimics protobuf varints, which are little-endian. Sqlite uses big-endian varints, and uses all 8 bits of the ninth byte.

[sbinet]

nice catch!

LGTM modulo a few nitpicks:

• could you reformat your commit message to look more like:

  
  sqlite3: blabla ...

This CL fixes foo because bar. Some more context.

- could you add another commit where you add yourself to the AUTHORS and/or CONTRIBUTORS files ?

sqlite3: add Zellyn Hunter to A+C

thanks a lot!

(I am preparing the move to a proper `go-sqlite` organization)

[sbinet]

(also, probably add a Fixes #4. at the end of the first commit message)

[zellyn]

ptal. Not sure on the normal rules for A vs C, so just added to C for now.

[sbinet]

thanks. usually, (but IANAL) for individuals, it's the A+C. (I am just piggy backing on what the Go and Gonum projects do.)

Let me know if you want to also sign the A, or want to keep it as is. (and I'll merge and migrate to go-sqlite/sqlite3)

[zellyn]

Added to both.

[sbinet]

thanks again!