ASPECT code for Fraters etal Cascadia paper

This is based on a recent ASPECT master branch (commit hash 38ef6dc) with some custom unmerged changes to for example add the CPO modules. This release is to archieve the state of the code as used in the Fraters, Billen, Naliboff, Staisch, Watt and Li paper on Using Subducting Plate Motion to Constrain Cascadia Slab Geometry and Interface Strength.

ASPECT code for Fraters and Billen paper on CPO in ASPECT

This is based on a recent ASPECT master branch (commit hash 0958759) with some custom unmerged changes to for example add the CPO modules. This release is to archieve the state of the code as used in the Fraters and Billen paper on implementing and using CPO (D-Rex) in a geodynamics code (ASPECT).