javadoc - BoardApp
bug fixed - BoardApp.post(user, project, postId) throws NullPointerException if the postId does not exist.
Merge pull request #66 from kjkmadness/doc/BoardApp

BoardApp javadoc 추가, 오류수정
Merge pull request #67 from npcode/javadoc/issue-label-app

javadoc: Add javadoc for IssueLabelApp.
attachment: Add notices to each temp attachments.

Add notices "This will be attached if you save" to each temp
attachments.