Renamed example plugins.json file

It's not really temporary, so tmp isn't a sensible suffix.  It's
provided in the distribution of the package, so dist is.

README.rst

 Usage
 -----
 
-1. Copy plugins.json.tmp to ~/.config/kaylee/plugins.json and fill the
+1. Copy plugins.json.dist to ~/.config/kaylee/plugins.json and fill the
    ".shell" section of the file with sentences to speak and commands
    to run.
 2. Run Kaylee with ``./kaylee.py``. This generates a language model and

setup.py

     install_requires=["requests", "setuptools"],
     data_files = [
         ("/usr/share/kaylee", ["data/icon_inactive.png", "data/icon.png",
-            "options.json.tmp"]),
+            "plugins.json.dist"]),
         ("/usr/lib/systemd/user", ["systemd/kaylee.service"])
     ],
     entry_points = {