v0.7.0

• Adds support for lists as top-level container in non-nested MutableJson type (via edelooff#51)
• Renames base classes for (nested) mutable containers to be more consistent between one another (now MutableContainer and
  NestedMutableContainer) (via edelooff#52)
• Adds mypy to test extra dependencies, allowing for single-step installation of requirements (via edelooff#50)