"lib" has used the variables "red", "green", "yellow", "blue", and
"purple" for outputting logs to stdout/stderr. On the other hand,
"themes" has used the same variables for including escape sequences in
PS1. These two sets of variables have different values, i.e., the
latter is enclosed by '\[' and '\]' and contains escaped '\e', which
means that there have been variable conflicts. In this commit, more
specific variables are used in these places to resolve the conflicts.
