Merge pull request github#2926 from github/mdbs-are-people-too

Unity: ignore mdbs, fix path to crashlytics file, make AssetStoreTools optional

Unity.gitignore

@@ -4,7 +4,9 @@
 [Bb]uild/
 [Bb]uilds/
 [Ll]ogs/
-[Aa]ssets/AssetStoreTools*
+
+# Uncomment this line if you wish to ignore the asset store tools plugin
+# [Aa]ssets/AssetStoreTools*
 
 # Visual Studio cache directory
 .vs/
@@ -26,12 +28,14 @@ ExportedObj/
 *.booproj
 *.svd
 *.pdb
+*.mdb
 *.opendb
 *.VC.db
 
 # Unity3D generated meta files
 *.pidb.meta
 *.pdb.meta
+*.mdb.meta
 
 # Unity3D generated file on crash reports
 sysinfo.txt
@@ -41,5 +45,5 @@ sysinfo.txt
 *.unitypackage
 
 # Crashlytics generated file
-Assets/StreamingAssets/crashlytics-build.properties
+crashlytics-build.properties