Release 1.0.2 Expand API, implement multi-threading for GVRS

This release expands the Gridfour software library to include a more well-rounded API for the Gridfour Virtual Raster Store. It also initiates a new set of utility classes for rendering applications, including support for Color Palette Table (CPT) files.

The GVRS file writing operations now support optional multi-threaded processing for performing data compression. This enhancement can reduce the time to write GVRS files by more than half.