Squashed 'core/' changes from dde87e5..3226f7a

3226f7a Throw IllegalArgumentException where necessary
3e99c62 Merge branch 'develop' into feature/issue297-wizard
2cf97cc Merge branch 'bugfix/issue316' into develop
2e61e7f Add tests to TestSuite
8fb5462 Add detailed test for #316 and fix it; fix to be discussed though.
c563ef7 Reproduce issue #316
10a69cd Merge branch 'feature/issue297-oauth' into feature/issue297-wizard
7a604b1 Merge branch 'develop' into feature/issue297-oauth
ec05d02 Allow TM.init() to alter the transfer settings (Flickr plugin needs this)

git-subtree-dir: core
git-subtree-split: 3226f7a8341dd55499a6597ea662d1ddd06de848
Merge commit '240e78643b9fdae3eb97e85efa6e650a1935c454' into feature/issue297-wizard