Files not correctly added/removed from index

Issue #32 : Updated concatenation of filepath and filename to prevent double backslash
Issue #60 : If a file is copied into scanned folder, and the lastModified date is before the scandate, an additional check is done to see if the file does exist in the index. If not, it will also be added. This is because the creation date is not present in the child object.

The code changes work for me on Windows, and files are really removed from the index. I am currently not able to test on Linux.