Starting work on moving to a WAR file format.

Adding a simple web.xml that contains just a single servlet.
Load JSON schema types from classpath resources.

java-json-schema v1.0.1 now supports loading schema types from the
classpath as resources, using the JSONResourceType class.

SkeletonServlet had been using the File constructor to SchemaEnv, which
loads the types from the filesystem ; however, this configuration won't
work in an environment where we're deploying as a WAR file.

So instead, I've converted SkeletonServlet to load all the types it
expects from the classpath as resources.  All the schemas are currently
in the package 'schemas'.
Running integration tests in Tomcat.

Updated the pom.xml to use Surefire to run integration tests (all
*ServiceTests.java files) during the integration-test phase, and to use
Tomcat to do it.
The TestServlet now just says, "OK".
Added first integration-test, of the TestServlet.