Flatten API (#274)

Re-exports types from the toplevel instead of placing them in individual
modules (often which only contain one type).

This makes the API easier for users to navigate, while still retaining
the same module structure internally.

Additionally, this commit uses the `uuid` crate for modeling UUIDs.

src/mgm.rs

@@ -73,7 +73,7 @@ pub(crate) const DES_LEN_3DES: usize = DES_LEN_DES * 3;
 #[cfg(feature = "untested")]
 const ITER_MGM_PBKDF2: u32 = 10000;
 
-/// Management Key (MGM) key types (manual/derived/protected)
+/// Management Key (MGM) key types (manual/derived/protected).
 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
 pub enum MgmType {
     /// Manual
@@ -132,6 +132,7 @@ impl MgmKey {
 
     /// Get derived management key (MGM)
     #[cfg(feature = "untested")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
     pub fn get_derived(yubikey: &mut YubiKey, pin: &[u8]) -> Result<Self> {
         let txn = yubikey.begin_transaction()?;
 
@@ -157,6 +158,7 @@ impl MgmKey {
 
     /// Get protected management key (MGM)
     #[cfg(feature = "untested")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
     pub fn get_protected(yubikey: &mut YubiKey) -> Result<Self> {
         let txn = yubikey.begin_transaction()?;
 
@@ -187,6 +189,7 @@ impl MgmKey {
     ///
     /// This will wipe any metadata related to derived and PIN-protected management keys.
     #[cfg(feature = "untested")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
     pub fn set_default(yubikey: &mut YubiKey) -> Result<()> {
         MgmKey::default().set_manual(yubikey, false)
     }
@@ -198,6 +201,7 @@ impl MgmKey {
     ///
     /// This will wipe any metadata related to derived and PIN-protected management keys.
     #[cfg(feature = "untested")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
     pub fn set_manual(&self, yubikey: &mut YubiKey, require_touch: bool) -> Result<()> {
         let txn = yubikey.begin_transaction()?;
 
@@ -257,6 +261,7 @@ impl MgmKey {
     ///
     /// This enables key management operations to be performed with access to the PIN.
     #[cfg(feature = "untested")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
     pub fn set_protected(&self, yubikey: &mut YubiKey) -> Result<()> {
         let txn = yubikey.begin_transaction()?;