Cleans up Config class's PHPDoc references.
Fixes class references for Config class

Several references to `\Phinx\Config\Config` have been updated from `\ArrayAccess`, which I presume is a vestigial reference.
Fixes incorrect and missing PHPDoc class references.
Removes unused use statements.
Updates PHPDoc with missing parameter types and @throws statements.
Fixes return types, PHPDoc input references

- a bunch of void methods weren't returning void.
- fixes a bunch of undefined variable errors.
- fixes PHPDoc statements to more specifically define array types.
- removes return statements on constructors.
Removes PRIMARY KEY column type

Primary key is a column option/attribute, not a column data type. References to this deprecated concept are removed. Users should be unaffected by this change, as the column type had an undefined constant, and therefore would have prevented any attempts to use it.
Merge pull request #237 from cyrusboadway/bugfix/undefined-constant

Removes PRIMARY KEY column type
Removes commented out variable assignments.
Merge pull request #236 from cyrusboadway/feature/code-cleanup

Code cleanup
Removes 'primary key' column type reference from documentation.
Merge pull request #245 from cyrusboadway/docs/remove-PK-reference

Removes 'primary key' column type reference from documentation
Merge pull request #246 from robmorgan/0.3.x-dev

update master