Only import pkg_resources where it's needed

Apparently it's really slow

spacy/cli/download.py

@@ -6,7 +6,6 @@ import requests
 import os
 import subprocess
 import sys
-import pkg_resources
 from wasabi import Printer
 
 from .link import link
@@ -87,6 +86,8 @@ def download(model, direct=False, *pip_args):
 
 def require_package(name):
     try:
+        import pkg_resources
+
         pkg_resources.working_set.require(name)
         return True
     except:  # noqa: E722

spacy/cli/validate.py

@@ -1,7 +1,6 @@
 # coding: utf8
 from __future__ import unicode_literals, print_function
 
-import pkg_resources
 from pathlib import Path
 import sys
 import requests
@@ -109,6 +108,8 @@ def get_model_links(compat):
 
 
 def get_model_pkgs(compat, all_models):
+    import pkg_resources
+
     pkgs = {}
     for pkg_name, pkg_data in pkg_resources.working_set.by_key.items():
         package = pkg_name.replace("-", "_")

spacy/util.py

@@ -2,7 +2,6 @@
 from __future__ import unicode_literals, print_function
 
 import os
-import pkg_resources
 import importlib
 import re
 from pathlib import Path
@@ -253,6 +252,8 @@ def is_package(name):
     name (unicode): Name of package.
     RETURNS (bool): True if installed package, False if not.
     """
+    import pkg_resources
+
     name = name.lower()  # compare package name against lowercase name
     packages = pkg_resources.working_set.by_key.keys()
     for package in packages: