process.cwd() won't find peer dependency if located in other directory

[alteredtastes]

line 8 /lib/tsc.js assumes the peer typescript dependency is in same directory as where the process began. it would be great to have an optional arg for indicating where exactly the typescript peer dependency is.

When I cd ./app and run ttsc, ttsc can't find the peer dependency from ./build/node_modules

projects/
   tsconfig.base.json
   build/
        node_modules/typescript/
   app/
        tsconfig.json (extends tsconfig.base.json)
   admin/
        tsconfig.json (extends tsconfig.base.json)
   core/
        tsconfig.json (extends tsconfig.base.json)

[cevek]

PR welcome