Implemented options for sanitizing static file paths.

### This adds 4 new system settings:

staticsaver.filename_sanitize (*Default: "No"*)
staticsaver.filename_sanitize_search (*Default: "[^\w\.]"*)
staticsaver.filename_sanitize_replace (*Default: "_"*)
staticsaver.preserve_case (*Default: "Yes"*)

The en lexicon file has been updated, however the ru (Russian) one has not.