mkdir: exit with error if no directory given
tr: use SmallIntMap instead of HashMap
Merge pull request #179 from ebfe/mkdir

mkdir: exit with error if no directory given
Merge pull request #178 from ebfe/comm

comm: add --version and --output-delimiter
tr: use BitvSet instead of HashSet
tr: add --complement
tr: add -c/-d tests
Merge pull request #180 from ebfe/tr

tr: speed up and add '--complement'
md5sum: update rust-crypto
Merge pull request #181 from ebfe/fix-build-master

md5sum: update rust-crypto
Adapt to removal of ~str from libstd.
Remove the now unnecessary conversion of os::args() ret val.
Merge pull request #183 from ebfe/fix-build-master

Adapt to removal of ~str from libstd.
Implement touch

Squashed commit of the following:

commit 7b7981d315dd7748287bedc8f6417bbc2f9cb1ee
Author: Nick Platt <platt.nicholas@gmail.com>
Date:   Sat May 24 00:33:49 2014 -0400

    Last minute touchups

commit dae70f52e2b485695e8c7e2ce8d2997f571afcab
Author: Nick Platt <platt.nicholas@gmail.com>
Date:   Fri May 23 23:43:24 2014 -0400

    Minor indentation fixes

commit 782a02fe2768cf9e457bb6db9e8a63615c3a4bd1
Author: Nick Platt <platt.nicholas@gmail.com>
Date:   Fri May 23 23:40:57 2014 -0400

    Fixes for latest rust

commit 51b0e59f75352bf65c89d2ab8cf0948da8404753
Author: Nick Platt <platt.nicholas@gmail.com>
Date:   Sun Apr 27 15:15:29 2014 -0400

    Fixups

commit 9efd1f4c07f4610e3067a5b2bd047eb117344cdf
Author: Nick Platt <platt.nicholas@gmail.com>
Date:   Sun Apr 27 14:20:11 2014 -0400

    Basic date and timestamp support

commit a354bc9c07a6ed2cd2748f1734a1ce0f6683e58c
Author: Nick Platt <platt.nicholas@gmail.com>
Date:   Sun Apr 27 01:37:37 2014 -0400

    Primary functionality in place

commit 8bbaa0caa34fbca129db0c86f32d376d6eafbe18
Author: Nick Platt <platt.nicholas@gmail.com>
Date:   Sat Apr 26 22:23:16 2014 -0400

    Support creating files

commit 5bf47c3c790b556b596d25a05cd74ca4c06b6d67
Author: Nick Platt <platt.nicholas@gmail.com>
Date:   Mon Apr 21 00:24:49 2014 -0400

    Add touch with basic usage text
Merge pull request #184 from caipre/master

Implement touch
Update rust-crypto
Merge pull request #185 from ebfe/fix-build-master

Update rust-crypto
StrBuf was renamed to String
Fix deprecation warnings
Merge pull request #187 from ebfe/fix-deprecation

Fix deprecation warnings