Finish download and search function. Not complete php unit test.
Need refactor book model
Merge remote-tracking branch 'origin/WLB' into WLB

Conflicts:
	Server/application/config/routes.php
	Server/application/controllers/download_controller.php
	Server/application/controllers/search_controller.php
	Server/application/controllers/user_controller.php
	Server/application/models/book_model.php
	Server/tests/controllers/UploadControllerTest.php