Modify SWAG import to find `swag` directory

[delphidabbler]

At present, when importing SWAG snippets, the user is expected to enter the path to the swag sub-directory of the download.

It would be helpful that, if the user instead provides the directory where the zip file was unzipped if the code look for the swag sub-directory and switch to it.

In pseudo code:

if provided directory does not end in `swag` then
  check if `swag` is a subdirectory of the provided directory
  if so then
    add `swag` to the provided directory
  else
    exception
  endif
endif