add checker for contest archive ZIP.
update .gitignore.
remove redundant setting constants.
use AppExceptionUtil to validate file is not null.
modify exception message and file type validation for reusing.
reuse ZipDataChecker.
throw exception when no test data file in problem information directory.
fix coding style issue
fix unit tests.
remove the limit for problem information directory name.
update .gitignore.
add a ZipDataChecker object as a field of ContestZipChecker.
remove redundant setting.
Merge pull request #45 from pfctgeorge/contest-management

add checker for contest archive ZIP.
change import order rule for projects.
optimize imports to fit the new order rule.
Merge pull request #48 from pfctgeorge/java-style-imports-order

Java style imports order
Fixes #5 - do not use c:url tag for BBS link.
Merge pull request #51 from lyhypacm/develop

Fixes #5 - do not use c:url tag for BBS link.
Do not show admin's status forever.