nrepl-emit-interactive-output is now in cider-

clojure-test-mode was silently failing on running tests, but reported
this as an error at compilation.
clojure-test-clear has an unused callback parameter

Removes unused, optional callback from clojure-test-clear that is not
used at point of call or inside of clojure-test-clear.

Please revert if needed for some other reason.
catch error in clojure-test-mode to prevent user-visible error

The `nrepl-current-connection-buffer` in current CIDER now throws an
error when there is no connection, so this breaks initialization of
`clojure-test-mode`, especially during startup.

This small change fixes this problem
Merge pull request #189 from alexott/master

catch error in clojure-test-mode to prevent user-visible error
Merge pull request #184 from dgtized/rename-nrepl-to-cider

Rename nrepl-emit-interactive-output to cider