Add clipcopy() and clippaste() generic cross-platform CLI clipboard functions.

Change copydir, copyfile, and coffee plugins to use them, instead of the Mac-only `pbcopy` command.

plugins/coffee/coffee.plugin.zsh

@@ -6,11 +6,11 @@ cf () {
 }
 # compile & copy to clipboard
 cfc () {
-  cf $1 | pbcopy
+  cf $1 | clipcopy
 }
 
-# compile from pasteboard & print
-alias cfp='coffeeMe "$(pbpaste)"'
+# compile from clipboard & print
+alias cfp='coffeeMe "$(clippaste)"'
 
-# compile from pasteboard and copy to clipboard
-alias cfpc='cfp | pbcopy'
+# compile from clipboard and copy to clipboard
+alias cfpc='cfp | clipcopy'

plugins/copydir/copydir.plugin.zsh

@@ -1,3 +1,5 @@
+# Copies the pathname of the current directory to the system or X Windows clipboard
 function copydir {
-  pwd | tr -d "\r\n" | pbcopy
+  emulate -L zsh
+  print -n $PWD | clipcopy
 }

plugins/copyfile/copyfile.plugin.zsh

@@ -1,5 +1,7 @@
+# Copies the contents of a given file to the system or X Windows clipboard
+#
+# copyfile <file>
 function copyfile {
-  [[ "$#" != 1 ]] && return 1
-  local file_to_copy=$1
-  cat $file_to_copy | pbcopy
+  emulate -L zsh
+  clipcopy $1
 }