Bump up version number to 2.9.1

Author: michel-kraemer

README.md

@@ -31,7 +31,7 @@ You may also use [Maven](http://maven.apache.org/) to download bson4jackson:
     <dependency>
         <groupId>de.undercouch</groupId>
         <artifactId>bson4jackson</artifactId>
-        <version>2.9.0</version>
+        <version>2.9.1</version>
     </dependency>
 </dependencies>
 ```
@@ -41,7 +41,7 @@ following snippet to your `build.gradle`:
 
 ```gradle
 dependencies {
-    compile 'de.undercouch:bson4jackson:2.9.0'
+    compile 'de.undercouch:bson4jackson:2.9.1'
 }
 ```
 

build.gradle

@@ -5,7 +5,7 @@ apply plugin: 'java'
 apply plugin: 'eclipse'
 apply plugin: 'idea'
 
-version = '2.9.0'
+version = '2.9.1'
 group = 'de.undercouch'
 sourceCompatibility = '1.7'
 targetCompatibility = '1.7'