Some dependency hygiene and update to Boot 1.5.10

The web module doesn't really need to depend on tomcat and all of
the Spring Boot web stack, but users need a way to grab that stuff
quickly if they want it (hence the new starter).

Also removed all spring-boot-starter dependencies from core and
context modules.

spring-cloud-function-samples/function-sample-pojo/pom.xml

@@ -13,7 +13,7 @@
 	<parent>
 		<groupId>org.springframework.boot</groupId>
 		<artifactId>spring-boot-starter-parent</artifactId>
-		<version>1.5.9.RELEASE</version>
+		<version>1.5.10.RELEASE</version>
 		<relativePath/>
 	</parent>
 
@@ -27,7 +27,7 @@
 	<dependencies>
 		<dependency>
 			<groupId>org.springframework.cloud</groupId>
-			<artifactId>spring-cloud-function-web</artifactId>
+			<artifactId>spring-cloud-starter-function-web</artifactId>
 		</dependency>
 		<dependency>
 			<groupId>org.springframework.boot</groupId>