hr_report_manpower: make calculation of absent,present,rest-day employees more robust
hr_report_manpower: make calculation of absent,present,rest-day employees more robust


BT-csanchez/hr,dufresnedavid/hr,dufresnedavid/hr,alanljj/oca_hr,damdam-s/hr,gurneyalex/hr,macopedia/hr,abstract-open-solutions/hr,abstract-open-solutions/hr,akretion/hr,Vauxoo/hr,charbeljc/hr,xpansa/hr,feketemihai/hr,microcom/hr,Antiun/hr,thinkopensolutions/hr,acsone/hr,hbrunn/hr,Eficent/hr,raycarnes/hr,macopedia/hr,open-synergy/hr,feketemihai/hr,acsone/hr,iDTLabssl/hr,xpansa/hr,hbrunn/hr,damdam-s/hr,charbeljc/hr,gurneyalex/hr,Endika/hr,akretion/hr,raycarnes/hr,rschnapka/hr,VitalPet/hr,alanljj/oca_hr,microcom/hr,Antiun/hr,yvaucher/hr,yelizariev/hr,yelizariev/hr,vrenaville/hr,iDTLabssl/hr,thinkopensolutions/hr,rschnapka/hr,vrenaville/hr,Eficent/hr,yvaucher/hr,Endika/hr,VitalPet/hr,Vauxoo/hr,open-synergy/hr,BT-csanchez/hr