Update tests

Remove PHP 5.2
Add WordPress v4.0.1
Set required version to 5.3.2
Update readme
Merge branch 'master' into issue-599
Check PHP version on activate
Check PHP version on plugins loaded
Bump up required WP version
Move to activation hook
Add a link to Help page
Update readme.md
add waffle.io badge
Merge pull request #609 from waffle-iron/master

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Correct path for hm-backup so it's tests are run
Merge pull request #599 from humanmade/issue-599

Drop support for PHP 5.2
Minor code cleanup
move trailingslash calls out of the loop for performance
Better default WP_TESTS_DIR

Default the tests dir to wordpress-develop.dev/tests/phpunit

Also replaces the duplicate conform_dir method with `HM_Backup::conform_dir`
Remove the custom webhook service

It's going to be an extension
Remove extra slashes and semicolons
Make sure current_action fnction is loaded