v0.6.0

Features:

• Add Aggregators and Instances to libkiva. These are high level objects used for performing common functions when integrating Kiva into whole building simulation tools.
• Add the ability to define callback functions for convection algorithms. This is useful when a program calling into libkiva has a variety of algorithms to choose from.
• Boundary conditions now include the option of defining different convective temperatures for walls and slabs.

Fixes:

• Fix typo in copying of MoWiTT convection correlations.
• Fix issue where the top of exterior insulation could be part of both the wall-top and grade boundaries.