SPiCT for FIDEA workshop on Zanzibar 2020

Download spict_1.3.0.zip for Windows and run install.packages("PATH\TO\PACKAGE\spict_1.3.0.zip", repos=NULL) to install the package.

Download spict_1.3.0.tar.gz for Linux and Mac and run install.packages("PATH\TO\PACKAGE\spict_1.3.0.tar.gz", repos=NULL) to install the package.

retroEffortFix

Fix retro when only effort is used (closes #72)