Merge pull request #31 (1) "added command line utility to render templates..."

From: https://github.com/vrde/pystache/commit/7667a95e285bbf162e2425045999e07b7bfea5f9
Into: issue_31

Adds command-line script: pystache/commands.py

pystache/commands.py

+from pystache import Template
+import argparse
+import json
+from loader import Loader
+
+def main():
+    parser = argparse.ArgumentParser(description='Render a mustache template with the given context.')
+    parser.add_argument('template',  help='A filename or a template code.')
+    parser.add_argument('context', help='A filename or a JSON string')
+    args = parser.parse_args()
+
+    if args.template.endswith('.mustache'):
+        args.template = args.template[:-9]
+
+    try:
+        template = Loader().load_template(args.template)
+    except IOError:
+        template = args.template
+
+    try:
+        context = json.load(open(args.context))
+    except IOError:
+        context = json.loads(args.context)
+
+    print(Template(template, context).render())
+
+
+if __name__=='__main__':
+    main()
+