refactor(library): remove unnecessary 'standard' subdirectory

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
refactor(library): rename Makefile.common to Makefile

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
refactor(shell): remove obsolete tests

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>