ui.Common: add $yobi.confirm
project.Member: apply $yobi.confirm on delete button
ui.Common: add $yobi.ajaxConfirm
pullrequest: change the mechanism for getting related authors

- compare only 2 commits : the head of to-branch and merge commit
- execute only if the merge is successful
ui.Common: add sDescription param on alert, confirm, ajaxConfirm
Send notification mail in user's preferred language.

Add 'lang' field in User model and store user's preferred language every
time user send a request which has Accept-Language HTTP field(s) and/or
language preference in a cookie.

When Yobi send notification emails, it groups recipients by preferred
language and send the email to each group separately in the preferred
language.
fix broken tests
PullRequest: fix script error occurs in btnAccept unavailable
Merge branch 'fix-pullrequest-view-140303' of laziel/yobi

from pull request 664
Messages: fixed typo
Merge branch 'fix-test' of kjkmadness/yobi

from pull request 663
Fix a sql error while deleting a project

Problem: Ebean tries to find users by issue_id column which does not
exist while deleting assignees in a project. Here is the sql query.

    select t0.id c0
    from n4user t0
    where (issue_id) in (?)

Solution: Remove unnecessary cascade and fix project deleting to delete
assignees after deleting issues.

Note: I'm not sure why Ebean tries to find users by a non-existent
column.
Fix integrity violation while deleting a project

A Referential integrity violation has occured while deleting a project
because project_visitation which refers a project has not been deleted.
Merge branch 'feature/mail-in-user-preferred-language' of npcode/yobi

from pull request 646
Merge branch 'fix/sql-error-while-deleting-a-project' of npcode/yobi

from pull request 668
Merge branch 'message/typo' of whiteship/yobi

from pull request 666
Merge branch 'fix/project-visitation-integrity-violation-while-deleting-project' of npcode/yobi

from pull request 665
Merge branch 'pullrequest/related-authors' of kjkmadness/yobi

from pull request 649
FileUploader: XHR upload requires https connection on MSIE
add on .gitignore automatically generated keystore file