Added release notes.

Author: rstam

Release Notes/Change Log v1.7.1-Bson.txt

@@ -1,2 +1,4 @@
 BSON library changes from 1.7 to 1.7.1
 
+CSharp275Tests.cs
+    a minor change so test passes in 2013

Release Notes/Change Log v1.7.1-Driver.txt

@@ -1,2 +1,10 @@
 C#/.NET driver changes from 1.7 to 1.7.1
 
+MongoConnection.cs
+    LastUsedAt now set when data is sent or received, not when connection is returned to the pool
+    new IsExpired method checks both idle and life time
+
+MongoConnectionPool.cs
+    AcquireConnection is strict about discarding expired connections and replacing them with new ones
+    MaintainPoolSize has been simplified a bit
+    ReleaseConnection doesn't return expired connections to the pool

Release Notes/Release Notes v1.7.1.md

@@ -1,4 +1,27 @@
 C# Driver Version 1.7.1 Release Notes
 =====================================
 
-This is a minor release.
+This is a minor release. The only change is to strictly enforce the
+MaxConnectionIdleTime and MaxConnectionLifeTime settings. These used to be
+loosely enforced, and connections were sometimes allowed to be used for a
+bit longer. However, in certain environments (some firewalls, and in particular
+in Windows Azure) connections that exceed the limits by even a little bit are
+guaranteed to fail, so it is much safer to enforce these values strictly.
+
+An online version of these release notes is available at:
+
+https://github.com/mongodb/mongo-csharp-driver/blob/v1.7.1/Release%20Notes/Release%20Notes%20v1.7.1.md
+
+File by file change logs are available at:
+
+https://github.com/mongodb/mongo-csharp-driver/blob/v1.7.1/Release%20Notes/Change%20Log%20v1.7.1-Bson.txt
+https://github.com/mongodb/mongo-csharp-driver/blob/v1.7.1/Release%20Notes/Change%20Log%20v1.7.1-Driver.txt
+
+The full list of JIRA issues resolved in this release is available at:
+
+https://jira.mongodb.org/secure/IssueNavigator.jspa?mode=hide&requestId=13109
+
+Documentation on the C# driver can be found at:
+
+http://www.mongodb.org/display/DOCS/CSharp+Language+Center
+http://api.mongodb.org/csharp/current/