Add tests for relativePath.
Draft of relativePath() and makeScriptBundle().
Add Foundation framework and bump version.
Start using ASOC for path manipulation and file operations.

This is a work in progress. At this stage, the code is dirty and many tests do not pass.
Implement some path operations using NSURL.

I have defined a `_fileURL()` handler to be used
internally to build an NSURL object from a path
specification. The following handlers have been
re-written to use `_fileURL()`:

    absolutePath()
    basename()
    directoryPath() (was dirname())
    joinPath()
    splitPath()

Note that POSIX paths are returned by these handlers
by getting the `lastPathComponent`, `path`,
`relativePath` properties of an NSURL, which strip
a trailing slash if it exists. This is something
to keep in mind for updating the tests.
Update some tests.
Remove relativizePath() and skip related tests.
Add pathExists() handler.

This will be based on Cocoa in the future. For now,
it’s pure AppleScript.
Define pathComponents() handler.
Sort handlers alphabetically.
Define filter() and transform() handlers.
Update split()’s comment and parameter name.
Add tests for functional handlers.
Cosmetic change in readUTF8() and writeUTF8().
Update comment in which().
Add space to make Script Editor happy.
Update rm() and fix related tests.
Fix makeAlias() and related test.
Add a handler to create an empty script bundle.

This is first step towards the full support of
building script bundles, including resources,
script libraries, and so on.

The handler is based on the public, but currently
undocumented, Apple’s OSAKit API.
Fix recently introduced bug in rm().