Remove warnings about lacking specs.
Address warnings about unused variables and functions.
Add dialyzer makefile targets.
Fix dialyzer warnings.

Fixed:
pokemon_pb.erl:52: The pattern <Default, _> can never match since previous clauses completely covered the type <_,'none'>
pokemon_pb.erl:53: The pattern <Val, _> can never match since previous clauses completely covered the type <_,'none'>
protobuffs.erl:373: Invalid type specification for function protobuffs:encode_field_tag/2. The success typing is (non_neg_integer(),0 | 1 | 2 | 5) -> [integer(),...]
protobuffs.erl:387: Invalid type specification for function protobuffs:encode_varint/1. The success typing is (integer()) -> [integer(),...]
protobuffs.erl:393: Invalid type specification for function protobuffs:encode_varint/2. The success typing is (integer(),[integer()]) -> [integer(),...]

Safe to ignore:
pokemon_pb.erl:46: The variable _ can never match since previous clauses completely covered the type #pikachu{}
Remove commented-out code.
Remove more commented-out code.
Merge pull request #42 from basho/sdc-cleanup-warnings

Cleanup warnings