documentation polished, added links to modelling functions.
expand.formula sets original environment on the result.
r.squaredGLMM uses new function 'ranform' to produce rand-efx formula (removed dependency on lme4::findbars in favour to older .findbars).
r_squared_glmm.R: checks for availability of attached packages




git-svn-id: svn://svn.r-forge.r-project.org/svnroot/mumin@292 edb9625f-4e0d-4859-8d74-9fd3b1da38cb