implement elf loader

xencall/examples/version_capabilities.rs

@@ -0,0 +1,8 @@
+use xencall::{XenCall, XenCallError};
+
+fn main() -> Result<(), XenCallError> {
+    let mut call = XenCall::open()?;
+    let info = call.get_version_capabilities()?;
+    println!("{:?}", info);
+    Ok(())
+}