start date and end date added to production order doctype
Calender and gantt chart view added for production order doctype
Filters added
data type of start_date and end_date changed to datetime
fix - validations added for auto fetch of cost center
Merge pull request #2312 from neilLasrado/production-calender-sync

Production calender sync
Merge pull request #2356 from neilLasrado/cost-center-undefined-error-fix

fix - validations added for auto fetch of cost center
 FIX validate-bom wrong condition
fixed
Merge pull request #2349 from neilLasrado/validate-bom-fix

 FIX validate-bom wrong condition
Operations added in Production Order DocType
Auto-Fetch added to operations in Production Order DocType
made operations in production order read-only
capacity & duration of cycle added to workstation
workstation operation timings added
Workstation DocType Modified
end-date calculation logic added