Automatically exclude extraneous files from installer

[soda3x]

Update the NSIS script to always exclude anything that shouldn't be in the packaged release. Sometimes when testing you will get a mod_database.txt, install_directory.txt and there will be a pdb file generated. These should never end up in the package and so the script should be updataed to exclude them so that we don't have to remember to remove these files (which are usually pretty handy to keep around for dev work)

[soda3x]

Finished, but won't mark as completed until #71 is closed as there will be a config file needing to be added to this exclusions list

[soda3x]

Implemented now that #71 is finished