BIDS Validator data not installed
When installing pybids through pip using an archive (e.g. tarball, zip, instead of from github with `-e`), the data for the `BIDSValidator` is not installed, causing `BIDSLayout` to fail initating
```
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python3.6/dist-packages/bids/layout/layout.py", line 143, in __init__
    **kwargs)
  File "/usr/local/lib/python3.6/dist-packages/grabbit/core.py", line 419, in __init__
    self.index()
  File "/usr/local/lib/python3.6/dist-packages/grabbit/core.py", line 610, in index
    _index_dir(path, list(domains))
  File "/usr/local/lib/python3.6/dist-packages/grabbit/core.py", line 603, in _index_dir
    elif self._validate_file(full_path):
  File "/usr/local/lib/python3.6/dist-packages/bids/layout/layout.py", line 204, in _validate_file
    return self.validator.is_bids(to_check)
  File "/usr/local/lib/python3.6/dist-packages/bids/layout/validation.py", line 64, in is_bids
    conditions.append(self.is_top_level(path))
  File "/usr/local/lib/python3.6/dist-packages/bids/layout/validation.py", line 75, in is_top_level
    with open(join(self.rule_dir, 'fixed_top_level_names.json'), 'r') as f:
FileNotFoundError: [Errno 2] No such file or directory: '/usr/local/lib/python3.6/dist-packages/bids/layout/config/validator/fixed_top_level_names.json'
```
diff --git a/bids/layout/validation.py b/bids/layout/validation.py
index 7f10ac77..6bd5ef18 100644
--- a/bids/layout/validation.py
+++ b/bids/layout/validation.py
@@ -35,8 +35,7 @@ class BIDSValidator():
     """
 
     def __init__(self, index_associated=True):
-        self.rule_dir = join(dirname(abspath(__file__)), 'config',
-                              'validator')
+        self.rule_dir = join(dirname(abspath(__file__)),'config', 'validator')
         self.index_associated = index_associated
 
     def is_bids(self, path):
diff --git a/bids/version.py b/bids/version.py
index aa881794..57b957e2 100644
--- a/bids/version.py
+++ b/bids/version.py
@@ -65,7 +65,7 @@ def package_files(directory):
 
 extra_files = package_files('path_to/extra_files_dir')
 PACKAGE_DATA = {
-    'bids.layout': ['config/*.json'],
+    'bids.layout': ['config/*.json', 'config/validator/*.json'],
     'bids.reports': ['config/*.json'],
     'bids': package_files('bids/tests/data')
 }
['bids/version.py', 'bids/layout/validation.py']