Docs updated

docs/src/tips.md

@@ -0,0 +1,25 @@
+# Tips
+
+This page collects useful tips in using **Gnuplot.jl**.
+
+
+## Which terminal should I use ?
+`Gnuplot` provides dozens of terminals to display and export plots.  Here we report a few tips on how to exploit the most used terminals.
+
+### `wxt` and `qt`
+
+#### Mouse interactions
+
+### `dumb` and `sixelgd`
+
+### `cairopng`
+
+### `gif`
+see [Animations](@ref).
+
+### `pdf`
+
+### `latex` and `cairolatex`
+
+### `unknown`
+This is a *dummy* terminal, it produces no output.  It is mainly used for debugging purposes.