Fixed erroneous return with a continue

This bug stopped the flushing of the event queue by returning too early
Merge pull request #347 from TheNeikos/fix-input_event_loop

Fixed erroneous return with a continue
Destruct the message when parser failure occured
Add checks whether there are statements or a statements array

To be able to deinitialize properly.
Merge pull request #348 from matthiasbeyer/add-json_deserializer_cleanup_on_failure

Add message destruction on failure
Add files for hotkey subsystem
Add list of mod keys
Add prototype for key evaluation function
Add file for hotkey DAG implementation
Add type definitions of DAG
Add (de)initialization of the hotkey DAG