[processing] R improvements

This commit:

Deletes Example scripts

Replaces Example scripts with more up to date versions

Adds general categories for r scripts: Basic statistics, Vector processing, Raster processing and Point pattern analysis

adds help files to all r scripts

Adds a groups of r scripts entitled Home range analysis, that includes Kernel href, LSCV Kernel, Minimum convex polygon, single linkage cluster analysis and characteristic hull method, using adehabitatHR()

Adds the following R scripts contributed by Yury Ryabov ( riabovvv(at)gmail.com ): Advanced raster histogram, Monte carlo spatial randomness, Relative distribution (distance covariate), Relative distribution (raster covariate),