ShellPkg: Rewrite’s Help.c to call the ShellPrintHelp function. 

also, adds a footer to the bottom of the “help” command to explain help switches. 

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Matt Stanbro <Matthew.A.Stanbro@intel.com>
Reviewed-by: Jaben Carsey <Jaben.carsey@intel.com>
Reviewed-by: Erik Bjorge <erik.c.bjorge@intel.com>


git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@14202 6f19259b-4bc3-4df7-8a09-765794883524
ShellPkg: Fixes CP function to prevent copying of files if destination does not have adequate storage.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Matt Stanbro <Matthew.A.Stanbro@intel.com>
Reviewed-by: Jaben Carsey <Jaben.carsey@intel.com>
Reviewed-by: Erik Bjorge <erik.c.bjorge@intel.com>


git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@14203 6f19259b-4bc3-4df7-8a09-765794883524