While we already support `VERBOSE` environment variable and
`CMAKE_VERBOSE_MAKEFILE` cached variable, add `-v` and `--verbose`
command line options to be able to activate verbose output directly from
CMake's build tool mode command line.
Also make `msbuild` honor the verbosity setting. `xcodebuild` still
doesn't honor the verbosity setting as it will need a policy added
and reworking of cmGlobalGenerator and cmsys to support
multiple command invocation.
Florian Maushart
439fe2e253