Bugfix/errors after merge (#15)

* bugfix/Fixed minor use-flag errors after merge

* bugfix/Additional changes for use-flag handling & Clippy fixes

* bugfix/missing feature check in test package

* bugfix/added use-flag for nks

Cargo.toml

@@ -23,7 +23,7 @@ debug = false
 strip = "symbols"
 
 [features]
-nks = ["core", "x25519-dalek"]
+nks = ["core", "x25519-dalek", "hcvault"]
 android = ["robusta_jni", "libloading", "tracing-android", "x25519-dalek"]
 debug = []
 hsm = []