Rewriting Rule Handling

Introduces inheritance of speech rules from an abstract base locale.
Speech rules are separated into dedicated precondition and action files. Speech rules are only formed when an action is given of an existing precondition.
The idea is that effectively only actions have to be localised. While new rules or preconditions can still be added, the majority can be inherited from the common base locale.
Minimises rule sets for each locale:
- Mathspeak sets are already minimised
- Clearspeak might still contain some redundancy

Bug fixes