Draft work on multiple attachment upload.
Update file list read logic.

So that if a directory is encountered it will read the contents of the
directory whilst if the recursive flag is specified all nested
directories are searched.
Improve file list read logic.
Update file list read logic.

Handle relative paths correctly.
Support multiple file upload.
0.1.149
Support uploading attachments in app/deploy|push.
0.1.150
Assert on --recursive file upload.
Assert on multiple file uploads.
0.1.151