bots: Add dependencies management.

Adds the file api/bots_api/provision.py that installs dependencies
for bots using pip. This file is also used by run.py when running
a bot. However, for testing, you need to separately provision the bots.

bots/.gitignore

@@ -0,0 +1 @@
+bot_dependencies

bots/thesaurus/requirements.txt

@@ -0,0 +1 @@
+PyDictionary

bots/thesaurus/thesaurus.py

@@ -2,11 +2,7 @@
 from __future__ import print_function
 import sys
 import logging
-try:
-    from PyDictionary import PyDictionary as Dictionary
-except ImportError:
-    logging.error("Dependency Missing!")
-    sys.exit(0)
+from PyDictionary import PyDictionary as Dictionary
 
 #Uses Python's Dictionary module
 #  pip install PyDictionary