Fix problem with node_modules in home directory

[garrows]

I had someone at a workshop run npm init in their home directory. Even though they changed directory to tessel-code later, npm install will look a few directories up for a package.json file and put node_modules in there. This being the home directory, npm actually refuses to use ~/node_modules when running (but not install).

[johnnyman727]

Good catch! Thanks @garrows.