misc: move .png files to "misc" dir and exclude it from packaging

Cargo.toml

@@ -1,7 +1,13 @@
 [project]
+
+# Project metadata
 name = "rbpf"
 version = "0.0.1"
 authors = ["Quentin Monnet <quentin.monnet@6wind.com>"]
 
+# Packaging directives
+exclude = ["misc/*"]
+
 [dependencies]
+
 libc = "0.2.0"

README.md

@@ -1,6 +1,6 @@
 # rbpf
 
-![](rbpf_256.png)
+![](misc/rbpf_256.png)
 
 Rust (user-space) virtual machine for eBPF