Add Vagrantfile, document use

* Adds workaround to setup.py for issue with Vagrant sync filesystem and
  hard linking (used by distutils in Python < 2.7.9). This workaround is
  only used in a Vagrant environment.
* Adds Vagrant-related files to .gitignore

setup.py

@@ -5,6 +5,12 @@ import re
 
 from setuptools import setup
 
+# Workaround for http://bugs.python.org/issue8876, see
+# http://bugs.python.org/issue8876#msg208792
+# This can be removed when using Python 2.7.9 or later:
+# https://hg.python.org/cpython/raw-file/v2.7.9/Misc/NEWS
+if os.path.abspath(__file__).split(os.path.sep)[1] == 'vagrant':
+    del os.link
 
 def read_file(filename, encoding='utf8'):
     """Read unicode from given file."""