Old files -> slickProject and created Gradle

Gradle project uses libGDX instead of Slick2d
Restructured Gradle, create hargen proj
Tutorial linked
assets restructure
Fixed broken resource link
restructure
Rain Drop testing program
Mini-game implemented as an exploratory game library test
Remove old slickProject files

Exported to sister repo
Merge pull request #1 from OHARG/Drops-Experiment

Drops experiment