LIBCLOUD-396: Do not set Content-Length if present in raw requests

Signed-off-by: Tomaz Muraus <tomaz@apache.org>
Add a comment which clarifies why Content-Length: 0 is not sent if "raw" mode is
used.
Update changes.
Fix test failure - use libcloud.test.unittest which correctly uses unittest2 in
Python < 2.7.
Use string instead of number for RecordType enum value and get rid of nasty
__repr__ hack.
Remove old RecordType definition.
docs: Fix a couple of typos, include correct tables.
Update changes.
Merge branch 'use_string_for_record_type_value' into trunk
Add methods for exporting Libcloud Zone to BIND zone format.
Update CHANGES.
Fix the function name.
Add documentation for new functionality.
Use a better function name.
Issue LIBCLOUD-397: Add an IBM SCE Windows node example to documentation

Signed-off-by: Tomaz Muraus <tomaz@apache.org>
docs: Add templates for common mailing list communication to the committer guide
section.
LIBCLOUD-399: avoid mutating AzureBlobsConnection at driver instance time

Signed-off-by: Tomaz Muraus <tomaz@apache.org>
Update changes.
Fix a typo.
Update Azure driver - host argument should have precedence over key argument.