Replaced group expression.
Rewrote RuleReverser to accept and return a list of rules.
Rewrote Expander to use recursion and allow for unlimited depth.
Changed Expander to return the list of combinations.
Updated RuleReverser, added expand method.
Added reverse lookup functionality.
Added mapping of back-references to rules.
Updated function replacement functionality.
Corrected sandhi file.
Created and corrected reverse sandhi file.
Updated SandhiReader.
Added functionality to SandhiRule.
Updated RuleReverser.
Added TODO annotation to RuleReverser.
Created class to remove duplicate rules from reverse sandhi file.