Merge pull request #861 from k-nasa/add_colored_help

Add colored help

Author: Dylan-DPC

src/main.rs

@@ -32,6 +32,7 @@ fn main() {
         .version(VERSION)
         .setting(AppSettings::GlobalVersion)
         .setting(AppSettings::ArgRequiredElseHelp)
+        .setting(AppSettings::ColoredHelp)
         .after_help(
             "For more information about a specific command, try `mdbook <command> --help`\n\
              The source code for mdBook is available at: https://github.com/rust-lang-nursery/mdBook",