- formulas like -1 + factor(x) will drop the first level of 'x' but not
  introduce an intercept. please check the 'vcrpart_formula_eta' function
- Give a warning if a random coefficient is called in fvcglm resp. tvcglm 
  function
- Check Gauss-Hermite integration points of the 'lme4' package
- Check if 'ucminf' works again
- Check nloptr package
- Illustration for tvcm and fvcm on wordpress page
- replace functions of the 'parallel' package with those of 'foreach'?
- variable importance measures
- there seems to be a problem with vcrpart_formula with 'terms' call: for example
  terms(diabetes ~ vc(z1,z2,x) + vc(z1,z2,by=x), specials = types, keep.order = TRUE)
   drops the second term!!!

- see the mail of Thomas Kalibera
- if no response available the message
   'Error in str(data.LONG2) : object 'data.LONG2' not found'
   appers
- note that the '/' operator does not work in formulas
- improve C code
- deal with empty target categories in olmm