minor be more helpful if someone tries to use a paths in a name

+ comment
specifying '.' for a name works for sources that are dirs or files

- remove isFile() check, allow dirs to use '.' name shortcut
- export TEMPLATE_RE
- use it to remove the template identifier

so this:

  mojito create path/to/some/foo .

creates ./foo using "foo" in template files for {{name}}. Makes
more sense for dirs than files anyway.