attachment: Add notices to each temp attachments.

Add notices "This will be attached if you save" to each temp
attachments.
added javadoc
refactoring Project class
fix admin delete user
changed order of condition
code: Rename parameters of CodeHistoryApp.
code/history: Fix and adjust exception handlings.
javadoc: Add javadoc for CodeHistoryApp.
added javadoc to ProjectUser
Merge pull request #68 from wansoon/javadoc

Project 클래스 javadoc 추가 및 리팩토링, 사이트 관리자의 사용자 삭제시 버그 수정
Merge pull request #74 from npcode/javadoc/code-history-app

javadoc: Add javadoc for CodeHistoryApp.
Merge pull request #58 from npcode/feature/temp-attachment-notice

attachment: Add notices to each temp attachments.
rename parameter and updated javadoc of PlayRepository
Merge pull request #70 from keesun/javadoc/play-repository

added javadoc to PlayRepository
utils.ReservedWordsValidator is added. see HIVE-212
add javadoc @ UserApp
UserApp refactoring
add sign-up form validation - email duplication
the email validation added @ user info modify form
Merge pull request #52 from kjkmadness/HIVE-212

[HIVE-212] 로그인 ID 에 예약어 사용할수 없도록 처리