Feature/fix dependencies

[phoenix741]

I propose this PR to fix #98.

There is two modification :

• include global pattern even when package individually is true.
• add an optimisation to not read the same file (i have 12 lambda individually packaged, with optimisation packaging take 79s, without, packaging take 152s; each lambda files is readed 3 times with predict.paperwork)

[phoenix741]

My modification will break this TU:

test('enables caching', t => {
  const instance = createTestInstance({ 
    serverless: {
      service: { custom: { includeDependencies: { enableCaching: true } } }
    }
  });
  const cacheEnabled = instance.cacheEnabled;
  t.true(cacheEnabled);
  const file = path.join(__dirname, 'fixtures', 'thing.js');
  const list1 = instance.getDependencies(file, [], cacheEnabled);
  const list2 = instance.getDependencies(file, [], cacheEnabled);

  console.log(list1);
  console.log(list2);
  t.true(list2.length < list1.length);
});

I'm not sur why because we read two time the same file, and the test thing to have two different result, but with the global cache, i have always the same result.