Now each command has a PreRun function that will execute before calling
the Run() function. This allows to show the banner and do some pre-check
work. Also moved parsePackagesFromDir() to the main function to avoid
getting called each time 'bee' is invoked.
Moved logging to the new logging infrastructure by removing the use of
ColorLog() function. Added more documentation. Also fixed some typos in
comments and function names.
Added a new Bee banner using ASCII art. When bee is invoked,
the banner is displayed with the version number (short banner).
A More verbose Banner is added to 'bee version' which shows
more information about the host and Go runtime.
