Closes #81: default to python2 and fallback to python

plugins/python/_python.fish

+# Use python2 if found, otherwise fallback to python.
+function _python
+  if which python2
+    python2
+  else
+    python
+  end
+end

plugins/python/pybeautifyjson.fish

 # beautify json string
 # use : pybeautifyjson '{"foo": "lorem", "bar": "ipsum"}'
 function pybeautifyjson
-  echo $argv | python -mjson.tool
-end
\ No newline at end of file
+  echo $argv | _python -mjson.tool
+end

plugins/python/pyhttp.fish

@@ -5,5 +5,6 @@ function pyhttp
   else
     set HTTPPORT 1025
   end
-  python -m SimpleHTTPServer $HTTPPORT;
+
+  _python -m SimpleHTTPServer $HTTPPORT;
 end

plugins/python/pysmtp.fish

@@ -5,6 +5,7 @@ function pysmtp
   else
     set SMTPPORT 1025
   end
+
   echo "smtp server started on port" $SMTPPORT;
-  python -m smtpd -n -c DebuggingServer localhost:$SMTPPORT;
+  _python -m smtpd -n -c DebuggingServer localhost:$SMTPPORT;
 end