Impacted versions:
10.0 + e

Steps to reproduce:
1) Create a salary rule that has 'appears_on_payslip' = False.
- An example would be a company contribution that the employee does not need to see.
  2) Add it to a salary structure
  3) run a payroll/payslip calculation

Current behavior:
Numerous thing.
1) Every time you compute sheet, you will duplicate these 'hidden' lines
2) details_by_salary_rule_category no longer has any of the hidden lines, though they certainly contribute to categories (e.g. tests will fail, and bad things)
3) when using hr_payroll_account, lines with contribution registers and accounts that SHOULD be on the journal entry are not !!

Expected behavior:
1) every time you compute the sheet, the lines should be deleted and recalculated
2) details_by_salary_rule_category should have all categories (to be able to make complex rules and tests)
3) journal entry should have a line for every line with an account

Pull Request eminent.

_name = 'hr.payslip.run'
    _description = 'Payslip Batches'
    name = fields.Char(required=True, readonly=True, states={'draft': [('readonly', False)]})
    slip_ids = fields.One2many('hr.payslip', 'payslip_run_id', string='Payslips', readonly=True,
        states={'draft': [('readonly', False)]})
    state = fields.Selection([
        ('draft', 'Draft'),
        ('close', 'Close'),
    ], string='Status', index=True, readonly=True, copy=False, default='draft')
    date_start = fields.Date(string='Date From', required=True, readonly=True,
        states={'draft': [('readonly', False)]}, default=time.strftime('%Y-%m-01'))
    date_end = fields.Date(string='Date To', required=True, readonly=True,
        states={'draft': [('readonly', False)]},
        default=str(datetime.now() + relativedelta.relativedelta(months=+1, day=1, days=-1))[:10])
    credit_note = fields.Boolean(string='Credit Note', readonly=True,
        states={'draft': [('readonly', False)]},
        help="If its checked, indicates that all payslips generated from here are refund payslips.")
    @api.multi
    def draft_payslip_run(self):