update .gitignore to include Visual Studio artifacts
diff --git a/.gitignore b/.gitignore
index f40064d..104e720 100644
--- a/.gitignore
+++ b/.gitignore
@@ -26,3 +26,10 @@
 
 # CMake generates *.dir/ folders for in-tree builds (used by MSVC projects), ignore all of those:
 *.dir/
+
+# Visual Studio artifacts
+/visualc/VS2010/.localhistory/
+/visualc/VS2010/.vs/
+/visualc/VS2010/Debug/
+/visualc/VS2010/Release/
+/visualc/VS2010/*.vcxproj.user