PyPartMC 0.0.21
- AeroState::deepcopy() (temporarily with hardcoded n_part=1) (thanks @jcurtis2!)
- shared_ptr semantics for AeroData and GasData within AeroParticle, AeroState and GasState
- use def_property_readonly instead of def for most of AeroState properties
- improved test coverage for AeroData, AeroParticle, AeroState and GasState