Permission issues with current location of cache directory

[pacoispaco]

I'm running proselint on a Linux (Ubuntu 12.04) machine. I get file permission denied when proselint tries to create the cache directory. I installed proselint with pip.

Reason: proselint attempts to create the cache directory in the install directory of proselint and that directory is owned by root.

Suggested solution: Create cache directory in a) current working directory or in b) /var/lib/proselint. Or provide a command line option to specify where to create the cache directory

To reproduce:
$ proselint /usr/local/lib/python2.7/dist-packages/proselint/demo.md
/usr/local/lib/python2.7/dist-packages/proselint
Traceback (most recent call last):
File "/usr/local/bin/proselint", line 9, in
load_entry_point('proselint==0.3.4', 'console_scripts', 'proselint')()
File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 700, in call
return self.main(_args, *_kwargs)
File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 680, in main
rv = self.invoke(ctx)
File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 873, in invoke
return ctx.invoke(self.callback, *_ctx.params)
File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 508, in invoke
return callback(_args, **kwargs)
File "/usr/local/lib/python2.7/dist-packages/proselint/command_line.py", line 166, in proselint
errors = lint(file, debug=debug)
File "/usr/local/lib/python2.7/dist-packages/proselint/command_line.py", line 65, in lint
module = importlib.import_module("checks." + check_name)
File "/usr/lib/python2.7/importlib/init.py", line 37, in import_module
import(name)
File "/usr/local/lib/python2.7/dist-packages/proselint/checks/garner/archaism.py", line 19, in
@memoize
File "/usr/local/lib/python2.7/dist-packages/proselint/tools.py", line 26, in memoize
os.mkdir(cache_dirname)
OSError: [Errno 13] Permission denied: '/usr/local/lib/python2.7/dist-packages/proselint/cache'