Clean up svn:ignore property and .gitignore in dart, dart/pkg, and dart/runtime.

dart/runtime/.gitignore

Index: dart/runtime/.gitignore
===================================================================
--- dart/runtime/.gitignore	(revision 15379)
+++ dart/runtime/.gitignore	(working copy)
@@ -1,41 +1,15 @@
-/*.filters
-/*.user
-/dart-runtime.sln
-/*.vcproj
-/*.vcxproj
-/*.mk
-/dart_no_snapshot.target.mk
-/dart-runtime.Makefile
-/dart-runtime.xcodeproj
-/dart.target.mk
-/generate_builtin_cc_file.target.mk
-/generate_corelib_cc_file.target.mk
-/generate_corelib_impl_cc_file.target.mk
-/generate_io_cc_file.target.mk
-/generate_isolate_cc_file.target.mk
-/generate_json_cc_file.target.mk
-/generate_mirrors_cc_file.target.mk
-/generate_snapshot_file.target.mk
-/generate_snapshot_test_dat_file.target.mk
-/generate_uri_cc_file.target.mk
-/generate_utf_cc_file.target.mk
-/gen_snapshot.target.mk
-/libdart_builtin.target.mk
-/libdart_export.target.mk
-/libdart_lib.target.mk
-/libdart_lib_withcore.target.mk
-/libdart.target.mk
-/libdart_vm.target.mk
-/libdart_withcore.target.mk
-/libdouble_conversion.target.mk
-/libjscre.target.mk
 /Makefile
-/process_test.target.mk
-/runtime
-/run_vm_tests.target.mk
-/test_extension.target.mk
 /out
+/runtime
 /xcodebuild
+/*.Makefile
+/*.sln
+/*.target.mk
+/*.vcproj
+/*.vcxproj
+/*.vcxproj.filters
+/*.vcxproj.user
+/*.xcodeproj
 /Debug
 /DebugARM
 /DebugIA32