fix/update javadocs
update LoadablePage: rename #getLoadablePage to #load
LoadablePage#load now handles checked exceptions
WebTask encapsulates the User running the task (the who)
fix UserTest after the change "WebTask has a User"
add concrete tasks ImLoggedIn and MyBrowserIsOpen
clenaup WebTask's: change TopWebTask to NavigationWebTask
cleanup WebTask's: drop MidChainWT
update javadocs in WebTask
WebTask: rename #doTask to #run
update pom: upgrade selenium-java to 2.44.0
add WebTest stuff

- WebTest
- JunitWebTest
- BrowserManager, TestRule for closing all browsers when a test finishes
- TestRetrier, TestRule for retrying failing tests
update SampleWebTest to use JunitWebTest
fix TestHelper: add javadoc, add private constructor
update pom: bump version to 0.2-SNAPSHOT