acme: support spaces in file names stored in acme.dump

[mbucc]

$ pwd
/Users/foo/Documents
$ mkdir test\ a \ space
$ cd test\ a\ space
$ 9 acme
   (Dump acme.dump, Exit)
$ 9 acme -l acme.dump

At this point, acme loads but prints the error "can't open /Users/foo/Documents/test: No such file or directory"

I tried a work around of dumping to a path without spaces, but that did not work.

ref: #331

[mbucc]

Workaround: don't use a dump file.

[mbucc]

This may be a related issue.

If you sweep a file path with a space in it, acme will not open a window for that directory.

For example, if you have an acme window for /a spacy dir/abc.txt and (on a Mac) you hold the Command key down and sweep the string /a spacy dir/ acme does not open a window for that directory.

Likewise, a Edit = and a subsequent Cmd-Click (again, on Mac) silently fails to open that file to that line.

[mbucc]

Workaround: Don't close the window displaying the project root directory when you first open acme.