Default build verbosity level

Context

The NEMO build process is fairly verbose by default. The verbosity level of most build-system calls made by makenemo can be controlled (option -v or --verbose), but in some instances it is fixed at 1; in corresponding calls made by tools/maketools it is either fixed or unspecified. Where the verbosity can be controlled, a default level of 1 is applied.

Proposal

It is proposed to make the verbosity level of the build-system calls made by makenemo and maketools controllable in unison via command-line option -v or --verbose, and to set a default level of 0 in order to keep the amount of standard output generated during the NEMO build process relatively low by default.