add delphi .dcu

.DCU (Delphi Compiled Unit) files are binary files that are used between compiling source (text) and linking the executable. They're created by the compiler, joined together in memory, combined with the startup code and put into an actual executable (.EXE/.DLL/.BPL) by the linker

Delphi.gitignore

@@ -50,3 +50,4 @@
 # Delphi history and backups
 __history/
 *.~*
+*.dcu