Use methods instead of standard PHP

By moving the standard functions move_uploaded_file and is_uploaded_file to methods within the class, we can override these methods in the test suite.

The two functions are only available during a POST.
Use new bootstrap file.

As we need to override two methods for testing we can bootstrap the original BulletProof class.

The new bootstrap file contains the new BulletProofOverride class used for testing.
Rewrite tests.

The current tests need to be rewritten as we are using the new approach of testing.
Copy the newly created file.

When we copy the new file we can do some more testing on it.
Fix new image location and name.

Give the new file a better name and set the upload dir to /tmp
Add bigger photo for future testing
Merge pull request #20 from petervanderdoes/feature/create_test_suite

Improve test suite