Feature/free phases

[andgoldschmidt]

This update fixes global data. This enables, e.g. free phase objectives and constraints.

New features:

• global nonlinear constraints
• global objectives
• adds global_data to optional kwargs of nonlinear constraints and objectives

TODO:

• testing for global_data kwarg
• testing for global objectives and global nonlinear constraint

[andgoldschmidt]

• Bump minor version when review passes before merging PR