Rename variables in inner scope to avoid shadowing outer variables of the same name.

Discovered with -Wshadow
Search bar filtering and sorting by file size in the file browser
Merge pull request #15 from DaidoujiChen/develop

Search bar filtering and sorting by file size in the file browser
Update changes and todo sections in the README
Fix “dead store” warning from the clang static analyzer.

We only use fullPath later. Subpath is only used temporarily to build the fullPath in one of the cases.
Use explicit nil initialization for consistency within the project.