SolStretch 1.0

Initial public release of SolStretch.
A Shiny app for enhancing contrast in parietal art and rock painting images using PCA-based decorrelation stretch.
Based on:

• https://gist.github.com/fickse/82faf625242f6843249774f1545d7958#file-decorrelation_stretch-r
• Partially based on http://dhanushkadangampola.blogspot.com/2015/02/decorrelation-stretching.html