Added Zhann theme. Based on Robbyrussel theme, but shows the current ruby...

Added Zhann theme. Based on Robbyrussel theme, but shows the current ruby version and has some color variations.

themes/zhann.zsh-theme

+PROMPT='%{$fg_bold[green]%}%p %{$fg[cyan]%}%c%{$fg_bold[blue]%}$(git_prompt_info)%{$fg_bold[blue]%} % %{$reset_color%}'
+RPROMPT='%{$reset_color%} %{$fg[red]%}$(~/.rvm/bin/rvm-prompt i v) %{$reset_color%}'
+
+ZSH_THEME_GIT_PROMPT_PREFIX=" (%{$fg[red]%}"
+ZSH_THEME_GIT_PROMPT_SUFFIX="%{$reset_color%}"
+ZSH_THEME_GIT_PROMPT_DIRTY="%{$fg[blue]%}) %{$fg[yellow]%}✗%{$reset_color%}"
+ZSH_THEME_GIT_PROMPT_CLEAN="%{$fg[blue]%})"