msvc: ignore .dll and incremental compile output

Ignore .dll files copied into the top-level directory.
Ignore MSVC incremental compiler output files.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

.gitignore

@@ -223,6 +223,11 @@
 *.user
 *.idb
 *.pdb
+*.ilk
+*.iobj
+*.ipdb
+*.dll
+.vs/
 /Debug/
 /Release/
 *.dSYM