Don't fail if no dry-run setting has been specified

Somehow we failed if no dry-run setting had been specified in the config
file. This got caught thanks to extending the test suite with a stock
configuration.

Signed-off-by: Sebastian Spaeth <Sebastian@SSpaeth.de>
Merge branch 'next'

Conflicts:
	Changelog.rst

Signed-off-by: Sebastian Spaeth <Sebastian@SSpaeth.de>
Merge branch 'next'
IMAPlib mixin class: pass 'readonly' exception to our callers

This will allow our callers who are capable of dealing with
readonly folders to properly detect this condition and act
accordingly.

One example is Gmail's "Chats" folder that is read-only,
but contains logs of the quick chats.

Tested-by: Abdó Roig-Maranges <abdo.roig@gmail.com>
Signed-off-by: Eygene Ryabinkin <rea@codelabs.ru>
Merge branch 'next'
fix typos
README.md: Renaming file so that github renders it nicely.
Fix small offlineimap.conf typo

Maxage comment 'therefor' -> 'therefore'.
Added remoteporteval
Merge pull request #36 from hobarrera/master

Renamed README to README.md
Merge pull request #35 from cpick/typo

Fix small offlineimap.conf typo
Correct whitespace & add docs about remoteporteval.
Merge branch 'dxtr-remoteporteval'
Merge pull request #28 from aspiers/fix-typos

fix typos
Merge branch 'master' into next