Typedef for parse completion blocks
Add model class for polygons, and refactor/simplify GPX parsing
Refactor GPX parsing and overlay creation into separate parser class and mapper protocol.
Begin refactoring parser tests: rename existing spec
Rename GPX directories to Parsers. Add missing NSArray+Functional dependency to podspec.
Split existing specs into parsing and mapping specs, and simplify both sets of specs.
Implement GPX to polygon mapper.