update .gitignore
add active ng-class to menu's li for active style.
Merge pull request #36 from mzry1992/mzry1992

Add contest rank list.
add travis configuration scripts to support travis.
fix building issue.
add script executation permission.
do not update apt
fix failed tests.
do not install maven dependencies before testing.
Merge pull request #38 from lyhypacm/travis-support

Add Travis support
Merge pull request #37 from pfctgeorge/nav-bar-style

Active menu tab style for current located unit.
change README file, add home page link and build status.
Merge pull request #39 from lyhypacm/develop

change README file, add home page link and build status.
check java style before testing.
Merge pull request #41 from lyhypacm/travis

check java style before testing.
remove submodule cdoj-ui and make cdoj-ui as a part of core.
Merge pull request #42 from mzry1992/cdoj-ui

Make cdoj-ui as a part of core.
multiple sample cases.
Merge pull request #43 from pfctgeorge/multiple-sample-cases

add support to multiple sample cases.
[UPDATE] Merge confilct