- get rid of the process dictionary;
- make tests run on any OS;

Original meck.erl was split into:
- meck - facade for entire library;
- meck_code_gen - code generation of mocked modules;
- meck_proc - satelite gen_server for every mocked module to
  maintain state (list of mocked functions, call history);
- meck_history - module that contains history digging functions;
- meck_util - misc stuff.

Function type specs were mostly put in place.

All unit tests pass.

Dialyzer issues only 3 sane warnings see
./dialyser.ingnore-warnings for details.

- meck_expect module was introduced to contain
  expectation construction and matching logic;
- history related types were moved to meck_history;

- meck_mod was renamed to meck_code;
- cyclic dependency between meck and meck_code_gen
  was removed.