problems:
- It doesn't support filenames with spaces.
- It inserts a space after the filename when tab-completing in an
"svn" command.
- Many people find it annoying that tab-completion on commands like
"tar" only matches filenames with the "right" extension.
- Lluís reported bash apparently crashing on some tab completions.
We should probably make this optional, and maybe use a subset of the
bash_completion file in the bash distribution that works.
svn path=/nixos/trunk/; revision=20179
0bae6c2c18