Update .gitignore for Windows/Visual Studio/GYP.

BUG=None
TEST=None

Review URL: https://chromiumcodereview.appspot.com/10701115
Patch from Sigurður Ásgeirsson <siggi@chromium.org>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12033 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

.gitignore

@@ -9,9 +9,11 @@
 *.pdb
 *.pyc
 *.scons*
+*.sln
 *.so
 *.suo
 *.user
+*.vcproj
 *.xcodeproj
 #*#
 *~
@@ -20,13 +22,16 @@ d8
 d8_g
 shell
 shell_g
+/build/Debug
 /build/gyp
+/build/Release
 /obj/
 /out/
 /test/es5conform/data
 /test/mozilla/data
 /test/sputnik/sputniktests
 /test/test262/data
+/third_party
 /tools/oom_dump/oom_dump
 /tools/oom_dump/oom_dump.o
 /tools/visual_studio/Debug