Add support for Dolphin Smalltalk

Smalltalk.gitignore

@@ -1,8 +1,11 @@
 # changes file
 *.changes
+*.chg
 
 # system image
 *.image
+*.img7
+*.img
 
 # Pharo Smalltalk Debug log file
 PharoDebug.log
@@ -10,6 +13,12 @@ PharoDebug.log
 # Squeak Smalltalk Debug log file
 SqueakDebug.log
 
+# Dolphin Smalltalk source file
+*.sml
+
+# Dolphin Smalltalk error file
+*.errors
+
 # Monticello package cache
 /package-cache