File type selection

[JoCastle]

Add functionality so that the user can select the type of file they want to look for: .tif and/or .pdf
Once user has chosen a folder pop up a window asking if the user wants .tif, .pdf. or both.
Answer sets a variable fed into the 'for' loop that sets whether the condition for taking the filename is

1. ends in '.tif'
2. ends in '.pdf'
3. ends in '.tif' or '.pdf'

[JoCastle]

Unnecessary as users should be able to link PDFs without a bulk linking file?