Change verbose mode to a verbosity level for the command line options

This is a patch to help fixing #41.
Should the default verbosity level stay the same as the previous `verbose` mode (i.e. the default stays `--verbosity 0`), or should we change it to `--verbosity 1` (i.e. we display `Loading component: componentX` lines by default)?
though dirty i did confirm the following in my console
```
undefined > 0
false
null > 0
false
0 > 0
false
```