Fix existing filepath check always returning true and adding path.

Stop trying to access the filePaths array as an object, thus returning
a falsey value (arrays don't have enumarable non-numerical properties)
and so always added the filePath to the filePaths array. This meant that
a template in project/ will never override the same template from a
library.
Merge pull request #5 from incuna/fix-duplicate-filepaths

Fix existing filepath check always returning true and adding path.