make sure modules path is short enough for Lmod
fix Tcl environment modules support

- run 'module use' on all module paths after changing $MODULEPATH
- also set $LD_LIBRARY_PATH_modshare when (re)setting $LD_LIBRARY_PATH
- also tweak stdout for purge/use module commands
- deprecate passing of list of module paths to run_module; not used, not needed, only complicates things w.r.t. 'module use' after touching $MODULEPATH