chore(composer): Remove composer lock file

Locking dependencies could cause problems if dependencies were updated
on one platform to versions that are incompatible with an older but
still supported platform. (E.g. updated on PHP 5.6 but then tests run
and fail on PHP 5.4 because dependencies are no good).
chore(cache): Add some new caching APIs for internal use
chore(datalist): Convert Datalist to use new caching APIs