🚧 Install as dependency broken in npm3

[heikomat]

When the project, that should get installed with minstall, is itself installed as dependency of another project using npm3, the installation fails. minstall thinks it was started outside the project root (because there is no node_modules folder in the project-folder) and thus aborts.

When minstall is called, it should be able to detect, that the project is beeing installed as dependency by checking if the second-to-last folder of process.cwd() is node_modules. If that is the case, it needs to not abort, but instead provide a proper node_modules-folder in the project-folder before starting the rest of the installation.

I'm working on this here: #15