v0.5.0

Over three years of improvements, including

• Rewriting local kronmult library and adding an optional global kronmult library
• Matrix-free implicit timestepping using GMRES or BICGStab solver
• IMEX time advance
• File checkpoint restart
• New PDEs

v0.4.0

• custom "kronmult" library added (https://github.com/project-asgard/kronmult) to drive explicit time advance.

• adaptivity added.

• currently, implicit timestepping and realspace transform only work for single-rank (local) runs.