1.1.0 Smarter Mixin Merges

[mkarlesky]

1. If :defines or :flags config or mixin conventions mismatch (array vs. matcher hash), the array is promoted to the hash-style * matcher automatically with a notice logging this modification.
2. An option has been added to the use of deep_merge() to handle the case of merging mixin single values into config arrays (typically a single string into an array of strings).
3. If some oddball edge case slips through both of the above, Ceedling now logs a warning explaining which mixin value will clobber a config value in a merge.