Improve Alerts to allow an alert to be displayed where off-hire overlaps.
Where we have off-hire periods that overlap, a warning alert should be displayed to highlight the fact that the off-hire periods overlap. If the total off-hire exceeds 100% at any point in time the Alert should prevent saving. We intentionally disabled the config setting that automatically created a reversal if two overlapping off hire periods exist at the same time, as this is a valid scenario where 2 different cranes (each @ 50% off-hire) breakdown at the same time.