Added functions sim1dBinom and sim2dBinom to simulate species occurrence (presence/absence) along environmental gradients
Corrected error in rbinom call and modified example
Changed rbinom call for multiple species
Corrected problem in sim2dPoisson for simulating multiple species
Corrected problem in sim2dNegbinom when simulating multiple species
add Binomial simulation from @Pakillo's PR with some modifications to affected files
ignore RStudio files; modified from @Pakillo's PR which didn't catch 'foo.Rproj' forms.
Merge branch 'Pakillo-master'