add prediction functionnality

Author: jugla

README.md

@@ -2,7 +2,10 @@
 ## General
 ![GitHub release](https://img.shields.io/github/release/jugla/pyWorldtidesinfo)
 
-Get tide info from World Tides Info server.
+Get tide info from World Tides Info server :
+- Location Parameter : latitude/longitude of monitored point
+- Tide prediction parameter : reference (LAT,...), tide station distance, tide prediction duration
+- Tide picture : unit (meter/feet), plot/background color
 
 ## Installing
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