Rewrote to work with webapi-parser

Major changes (BREAKING):

• Rewrote to work with webapi-parser (#205);
• New dependency: webapi-parser;
• Dropped dependencies: datatype-expansion, raml-1-parser;
• All the library API now accepts webapi-parser objects instead of JS Objects/JSON;

Minor changes:

• Updated dependencies' versions;
• Switched to const/let instead of var;

Performance:
Performance changes are described in the osprey-profiling repo.