Major refactor

• Change to proper callback structure (callback as the second argument to dependents, not as a success property of the first argument)
• Main export is now parallelized
  • Previously, only the binary was parallelized using clustering
  • Now, the whole library is parallelized (if the number of files meets/exceeds the threshold) using forks not clustering.
• Removal of the dependency lookup shell script in favor of the binary in node-module-lookup-amd
  • Didn't belong there to begin with but was convenient.
• Major refactoring for testability
  • Test coverage fell because it wasn't originally including the bulk of the parallelization logic in the binary.

Breaking: Api changes

1. Success callback is passed any errors (node-style) #37
2. Removed the .for() api and a simple function is exported now #36
3. CLI uses flags instead of positional arguments #40

Performance gain

Using an updated version of node-precinct that avoids double parsing files by sharing the generated AST.

Swallow esprima errors

A file that cannot be parsed should not stop the computation of the dependents nor affect its output.