Added public files

Roughly added all public files. Probably missed some, though.
diff --git a/doc/efun/log b/doc/efun/log
new file mode 100644
index 0000000..1b2abff
--- /dev/null
+++ b/doc/efun/log
@@ -0,0 +1,8 @@
+SYNOPSIS
+        float log(int|float arg);
+
+BESCHREIBUNG
+        Liefert den natuerlichen Logarithmus von <arg>.
+
+SIEHE AUCH
+        exp(E), pow(E)