Adding maven-compiler-plugin to pom to fix compilation errors running 'mvn clean install'

[michaellavelle]

Hi

Thanks for the great work on the spring-social-jpa project. I'd like to use your module in my project and although 'mvn install' worked without problems, 'mvn clean install' caused compilation errors such as 'generics are not supported in -source 1.3'. Adding this plugin to the pom resolves this - I thought you may want to pull this into your project?

Many thanks,

Michael Lavelle