Convert Pellet to build using Maven

This pull request converts the build to use Maven.

It includes the use of the findbugs plugin (using mvn -Pfindbugs clean install), but does not include support for cobertura at this point. The cobertura maven plugin isn't well suited to multi-module Maven builds at this point in time.

The majority of the file content changes are in tests to switch from direct file access (where possible) to using getClass().getResourceAsStream(...), to avoid copying the file out to the file system. There are a few cases where it is necessary to copy files out to the file system to satisfy some APIs. These are accommodated for in a new TestUtils helper function that copies the named resource from the classpath out to a JUnit TemporaryFolder. JUnit cleans up the file system after the test.

The file move changes, are to move to the standard Maven layout, to easily work with the standard maven plugins.

.classpath and .project were removed as they are not necessary anymore. They can be regenerated either using "mvn eclipse:eclipse" or by importing into Eclipse using M2E. 

https://maven.apache.org/plugins/maven-eclipse-plugin/eclipse-mojo.html