Initial commit for Sky Calendar tool. Here's an example of what I'm going for:
<a href="http://www.astroscu.unam.mx/~jdo/sky1999.htm">http://www.astroscu.unam.mx/~jdo/sky1999.htm</a>;

There's a lot TODO:
+ populating the plot is currently VERY slow, so you have to press the Update button when you open the tool (then go get some coffee!).

+ lines are unlabeled, but they represent the rise, set and transit times of all major solar system bodies (incl. Pluto).

+ The Horizons (which are the times of sunset and sunrise) are currently stored in pixel coordinates, so don't try to resize the plot yet

+ Currently I assume that the sun rises and sets daily, so locations near the poles will have problems.

+ To be added: Moon phases, twilight lines, better axis labeling

If anyone's interested in helping develop this tool, please feel free to join me!