Bug fixed in leave details + Updated specs

@Sanjiv: Please review changes.
Redirect back to current page after sign in
Cosmo change
Updated specs
Edit Leave application + validation for leave

1) Admin can edit leave
2) Employee can edit only own leave only if it is pending
3) Casual leave can't be more than 2 days
4) If sick leave is more than 3 -> Show notification to submit medical
certificate
Merge pull request #25 from anujaware/leave_application

Bug fixed in leave details + Updated specs