correct handling of ISO 8601 timezone format
correct handling of ISO 8601 timezone format
- Add ``colander.ContainsOnly`` and ``colander.url`` validators.
Add myself to CONTRIBUTORS.
Iso datetime format can be truncated.

Correct ISO8601_REGEX to support truncated time part in the
datetime representation, and add corresponding tests: now we support
time stamps truncated to the minute, the hour or the day:

    2007-01-25T12:00Z
    2007-01-25T12Z
    2007-01-25
Merge branch 'contributor_agreement' into iso8601_truncation
rename acceptable to choices
prep for 1.0a2
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'origin/master'

Conflicts:
	colander/iso8601.py
added some tests for #65 - handling of ISO 8601 timezone format
specify optional fields with "missing=drop"
Update colander/locale/nl/LC_MESSAGES/colander.po

typo in translation
Clean up whitespace.
Fix type re: issue #89.
Add Doug Latornell to contributors list.
Delete trailing whitespace.
Improve email address validator regex & add tests re: #82.
Merge pull request #94 from douglatornell/issue82

 Improve email address validator regex & add tests re: #82.
Merge pull request #85 from mrijken/patch-1

Update colander/locale/nl/LC_MESSAGES/colander.po