Prefer vim to vi for default editor (#4230)

* vim > vi
* Allow which to accept multiple args
* Update __init__ to use which with multiple args
* Fix doc tests

var/spack/repos/builtin/packages/hdf5-blosc/package.py

@@ -184,7 +184,7 @@ def check_install(self, spec):
                "-L%s" % spec["hdf5"].prefix.lib, "-lhdf5")
             try:
                 check = Executable("./check")
-                output = check(return_output=True)
+                output = check(output=str)
             except:
                 output = ""
             success = output == expected