Runs in file directory rather than project root

[jonvuri]

This plugin runs Flow in the directory containing the current file, rather than the root project directory Atom is open to, or the project root as defined by the first parent directory with a .flowconfig file. This creates a problem when you have a Flow config that depends on <PROJECT_ROOT> in order to resolve certain modules with module.name_mapper, causing errors that only occur in flow-ide but not when running flow from the project root directory.