[WIP] deconstructPathRelativeToSWD

Addresses fixes to deconstructPathname (addresses issue #264). Introduces a new function deconstructPathRelativeToSWD that finds the absolute path to a given path name relative to a specified working directory (swd).
The term "full absolute path" may be confusing. Perhaps just say "absolute path"? Once the `isAbsolute` boolean is renamed to something like `isSearchable`, "absolute path" won't be ambiguous anymore.