Crates io (#76)

* crates re-organisation

* fixed typo in layout & added test for vmp_apply

* updated dependencies

poulpy-backend/builds/cpu_spqlios.rs

@@ -1,7 +1,7 @@
 use std::path::PathBuf;
 
 pub fn build() {
-    let dst: PathBuf = cmake::Config::new("src/implementation/cpu_spqlios/spqlios-arithmetic")
+    let dst: PathBuf = cmake::Config::new("src/cpu_spqlios/spqlios-arithmetic")
         .define("ENABLE_TESTING", "FALSE")
         .build();