FEAT: Switch to using MaybeUninit for everything

Use std::mem::MaybeUninit and stop using nodrop as a fallback.
This means we require Rust 1.36

src/array_string.rs

@@ -17,7 +17,7 @@ use char::encode_utf8;
 #[cfg(feature="serde-1")]
 use serde::{Serialize, Deserialize, Serializer, Deserializer};
 
-use super::MaybeUninitCopy;
+use super::MaybeUninit as MaybeUninitCopy;
 
 /// A string with a fixed capacity.
 ///
@@ -98,10 +98,10 @@ impl<A> ArrayString<A>
     /// ```
     pub fn from_byte_string(b: &A) -> Result<Self, Utf8Error> {
         let len = str::from_utf8(b.as_slice())?.len();
-        debug_assert_eq!(len, A::capacity());
+        debug_assert_eq!(len, A::CAPACITY);
         Ok(ArrayString {
             xs: MaybeUninitCopy::from(*b),
-            len: Index::from(A::capacity()),
+            len: Index::from(A::CAPACITY),
         })
     }
 
@@ -114,7 +114,7 @@ impl<A> ArrayString<A>
     /// assert_eq!(string.capacity(), 3);
     /// ```
     #[inline]
-    pub fn capacity(&self) -> usize { A::capacity() }
+    pub fn capacity(&self) -> usize { A::CAPACITY }
 
     /// Return if the `ArrayString` is completely filled.
     ///