upgrade to rxjava 1.3.8, rxjava-extras 0.8.0.15

pom.xml

@@ -21,7 +21,7 @@
         <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
         <scm.url>scm:git:https://github.com/davidmoten/rxjava-jdbc.git</scm.url>
         <maven.compiler.target>1.7</maven.compiler.target>
-        <rxjava.version>1.3.7</rxjava.version>
+        <rxjava.version>1.3.8</rxjava.version>
         <cobertura.version>2.7</cobertura.version>
         <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
         <checkstyle.version>2.11</checkstyle.version>
@@ -85,13 +85,13 @@
         <dependency>
             <groupId>io.reactivex</groupId>
             <artifactId>rxjava</artifactId>
-            <version>1.3.7</version>
+            <version>1.3.8</version>
         </dependency>
 
         <dependency>
             <groupId>com.github.davidmoten</groupId>
             <artifactId>rxjava-extras</artifactId>
-            <version>0.8.0.14</version>
+            <version>0.8.0.15</version>
         </dependency>
 
         <dependency>