add multi key support

better exception messages

better key verification

only split on newline

use verbose config section

simplify key verification

remove redundancies

make expired keys explicit

key is required

fix some tests
Merge pull request #2303 from Particular/multiEncryptionKeys

add multi key support
Api now support setting the key via code.
Remove fluent from ConfigurationBuilder
Remove fluent from RijndaelEncryptionService methods