[fix #772] and fix broken `cider-eval-and-get-value`

   - rename `cider-eval-and-get-value` into `cider-sync-eval-and-parse`
Merge pull request #786 from vitoshka/master

[fix #772] and fix broken `cider-eval-and-get-value`
[#780] make sure to dispatch requests in connection buffer
don't dispatch to nrepl--make-default-handler and throw an error instead
[fix #750] make `nrepl-pending-requests` and `nrepl-completed-requests` truly local