check for directory? in WeirdMethodLocator#valid_file? prevents crash under jruby
hotfix for jruby issue #890
hotfix for jruby, fixes #890
reload-code (with no args) should reload 'current file'

This should fix #920.
Also added a guard for !code_object.source_file, this existed on 0.9.12
but for some reason was not on master.
version 0.9.12.2 release

resolved #920, reload-code (with no args) should reload 'current file'