Improve cli documentation for bulbs and power strips (#123)

docs/source/smartbulb.rst

@@ -1,6 +1,59 @@
 Bulbs
 ===========
 
+Supported features
+******************
+
+* Turning on and off
+* Setting brightness, color temperature, and color (in HSV)
+* Querying emeter information
+* Transitions
+
+Currently unsupported
+*********************
+
+* Setting the default transitions
+* Timers
+
+.. note::
+
+    Feel free to open a pull request to add support for more features!
+
+Transitions
+***********
+
+All commands changing the bulb state can be accompanied with a transition, e.g., to slowly fade the light off.
+The transition time is in milliseconds, 0 means immediate change.
+If no transition value is given, the default setting as configured for the bulb will be used.
+
+.. note::
+
+    Accepted values are command (and potentially bulb) specific, feel free to improve the documentation on accepted values.
+
+    **Example:** While KL130 allows at least up to 15 second transitions for smooth turning off transitions, turning it on will not be so smooth.
+
+Command-line usage
+******************
+
+All command-line commands can be used with transition period for smooth changes.
+
+
+**Example:** Turn the bulb off over a 15 second time period.
+
+.. code::
+
+    $ kasa --bulb --host <host> off --transition 15000
+
+**Example:** Change the bulb to red with 20% brightness over 15 seconds:
+
+.. code::
+
+    $ kasa --bulb --host <host> hsv 0 100 20 --transition 15000
+
+
+API documentation
+*****************
+
 .. autoclass:: kasa.SmartBulb
     :members:
     :undoc-members: