make userinfo to dropdown menu on navbar(HIVE-101), apply HIVE UI to board(HIVE-188), fix filter on board(HIVE-134), remove deprecated file (postValidate.scala.html), change default image of project(HIVE-213)
fix topmenu style as same with navbar
fix userinfo dropdown style of topmenu
apply HIVE CSS including trivial fix. delete milestone manage page that combined with milestone list page
javadoc/tag: Add javadoc for TagApp.
javadoc: RepositoryService
Fix errors and mistakes on 11.sql.

* Add missed semicolons.
* Remove the inappropriate trailing whitespace in 'Language ' value.
* Drop constraints and columns if only they exists.
* Drop constraints before drop related columns
* To avoid unique constraint violation for the name field,
    * Delete duplicated rows.
    * Prepend category to name.
added javadoc and code refactoring
label: Allow only members to edit labels.
added email validation on signup
added javadoc
label: Supplement IssueLabelApp's request handling

* Return 406 to a request for labels, if the client does not accept
  application/json.
* Return 403 to a request for labels, if the user does not have
  permission to access the project owns the labels.
* Add descriptive content bodies for 4xx errors.
* Rename the parameter 'userName' to 'owerName' to make it clear.
* Do not contain body in a response to a request for adding a label, if
  the client does not accept application/json.
javadoc - BoardApp
bug fixed - BoardApp.post(user, project, postId) throws NullPointerException if the postId does not exist.
javadoc: Add javadoc for IssueLabelApp.
AccessControl: refactoring
added javadoc to History
javadoc: Add javadoc for Tag model.
fix mixed conflicts
Update README.md

add required java version for installation