Follow Java conventions

[mcandre]

• Load src/test/resources/<static files>, not src/main/resources/<static files>
• Keep features and step definitions in src/test/cucumber/ and src/test/java respectively

Following these conventions avoids a lot of confusion and manual configuration. For example, step definitions that reference Hamcrest matchers fail to compile with test-context dependency hamcrest-library, forcing users to awkwardly specify hamcrest-library as a main (deployed dependency).