Name To Structure: investigate a feasibility of FSM-based parser for IUPAC grammar

Investigate if FSM-based (Finite State Machine) parsing approach is feasible for IUPAC grammar and its sub-dialects.

If applicable, FSM-based parsing could significantly improve maintainability of Name-To-Structure converter. However, defining rules for the whole IUPAC grammar with all its sub-dialects could be a hard task. Moreover, currently we're reluctant to use third-party parser generators like Bison due to license considerations; this might add additional burdens to this task.