Fix `iterpolate-script` memoization bug

Silly mistake- was memoizing over the script's argument _values_ (which
generally change on each call), killing any memoization benefit and
potentially consuming unbounded amounts of memory for heavy script users.
Parsers no longer mask exceptions by default

This is much more sensible behaviour and fixes a bug when `evalsha*` was
enclosed in a `with-parser` context. As a bonus, the new behaviour improves
general reply-parsing performance.

To reproduce the old behaviour (e.g. to write a parser that deals manually
with exceptions), attach {:throw-exceptions? false} metadata to your parser
fn.
Tweak `get-replies!` API (better break users outright)
Housekeeping
Add `utils/defonce*
Experimental distributed locks ns
Locks: remove unnecessary `pexpire` fallback
Locks: housekeeping
Add README content for new locks ns
Bump version (1.7.0-beta2)
Merge branch 'dev'