Minor updates to examples; primary for the optics and making examples runnable from docs.

Minor doc update

Minor tweaks to reduce confusion in docs & examples.

• Adds handler for global log from standard library.
  Any logging from a third-party library can be handled.
• Adds sorting of log-lines from global log from standard library.
  Allows you to assign appropriate logging levels or hiding them based on content inspection.
• More doc updates.

• API changes
  log.OptionMust(o Option, err error) has become log.OptionsMust(o Option, err error) to reflect the most appropriate use case, which is to check for errors from OptionLoaders combined through log.Options(opt ...interface{}).
• Minor doc updates and tweaks.