Added public files

Roughly added all public files. Probably missed some, though.
diff --git a/doc/efun/exp b/doc/efun/exp
new file mode 100644
index 0000000..c5746dc
--- /dev/null
+++ b/doc/efun/exp
@@ -0,0 +1,8 @@
+SYNOPSIS
+        float exp(int|float zahl);
+
+BESCHREIBUNG
+        Die Exponentialfunktion. Liefert e^zahl.
+
+SIEHE AUCH
+        log(E), pow(E)