Improved target path parsing for Config File.

Checking for "." anywhere in full filepath is a poor way of determining whether a path is to a file or a directory.  Naming conventions allow for periods in directory names and do not necessitate them in file names.  As plugin currently works, /a/path.with/periods would be parsed as a file but /a/path/to/readme would be parsed as a directory.

Plugin should assume target is specifying filename unless (1) path includes a trailing slash or (2) the path already exists in the workspace as a directory.