Make copyable values copyable

src/column.rs

@@ -9,6 +9,8 @@ pub enum Column {
     Inode,
 }
 
+impl Copy for Column { }
+
 // Each column can pick its own alignment. Usually, numbers are
 // right-aligned, and text is left-aligned.
 
@@ -16,6 +18,8 @@ pub enum Alignment {
     Left, Right,
 }
 
+impl Copy for Alignment { }
+
 impl Column {
     pub fn alignment(&self) -> Alignment {
         match *self {

src/filetype.rs

@@ -13,6 +13,8 @@ pub enum FileType {
     Image, Video, Music, Lossless, Compressed, Document, Temp, Crypto,
 }
 
+impl Copy for FileType { }
+
 static IMAGE_TYPES: &'static [&'static str] = &[
     "png", "jpeg", "jpg", "gif", "bmp", "tiff", "tif",
     "ppm", "pgm", "pbm", "pnm", "webp", "raw", "arw",

src/options.rs

@@ -12,6 +12,8 @@ pub enum SortField {
     Unsorted, Name, Extension, Size, FileInode
 }
 
+impl Copy for SortField { }
+
 impl SortField {
     fn from_word(word: String) -> SortField {
         match word.as_slice() {