add statistics module

provides some basic statistics functions (sum, mean, etc.)
and a function to return the parameters of the linear regression of
two variables

implemented using num_traits to be more flexible for the types

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>

src/api2.rs

@@ -5,6 +5,7 @@ pub mod config;
 pub mod node;
 pub mod reader;
 mod subscription;
+pub mod status;
 pub mod types;
 pub mod version;
 pub mod pull;