update to dll loading

Added fetch dll path through registry.

Added custom error class VBPathError in case dll path was not found

Added function Setup_DLL to base.ps1

Wrapper setup stops if setup_dll returns false (no login, no class setup)

lib/errors.ps1

@@ -1,3 +1,15 @@
+class VBPathError : Exception {
+    [String]$msg
+
+    VBPathError([String]$msg) {
+        $this.msg = $msg
+    }
+
+    [String] ErrorMessage() {
+        return $this.msg
+    }
+}
+
 class LoginError : Exception {
     [String]$msg