#293 accept manifests with differing path seperators to the os

[Terry O'Neill]

Currently when a manifest that was made on windows is loaded onto linux if there is any directory structure in the file paths provided then an error will result saying "Invalid Character". This is because the paths will use the \ character as a path seperator in this case whereas linux will expect a path seperator of /. The use of these file paths should be altered to allow for accepting either \ or / as the path seperator and converting this over for the operating system DPR is running on.