.bashrc: Add brew coreutils to $PATH

Need to have GNU-style coreutils installed to keep me sane. By
default all the coreutils will be installed with g* prefix. Need to
add "/usr/local/opt/coreutils/libexec/gnubin" at the start of $PATH
so that the coreutils versions win.

Also, remove Fink handling. Haven't used Fink in years now...
bin/ipaddr: Size column based on max if-name length