For correct prunning of the lockfile, it has to be known
which deps are optional. Also it has to be known which
deps are dev deps in the root.
BREAKING CHANGE:
lockfile format changed
* fix: global installation always works now
Close#711
* refactor: avoid using `read-pkg-up`
BREAKING CHANGE:
API should be called in the folder that has a package.json file.
pnpm won't search up for a package.json file.
Close#67
* docs(API): update
* refactor: write-pkg created dir on its own
* refactor: rename `globalDir` to `globalPrefix`
* feat: saving the global package in <global prefix>/pnpm-global
BREAKING CHANGE:
`rc` is not used to get configs.
BREAKING CHANGE:
`.pnpmrc` files are ignored
BREAKING CHANGE:
configs in json format are not supported
BREAKING CHANGE:
`--config` argument renamed to `--userconfig`
Close#696, Close#40
