LONDON (Reuters) - Royal Dutch Shell has postponed decisions on whether to go ahead with two large oil and gas developments in the Gulf of Mexico and North Sea after oil prices collapsed due to the coronavirus crisis, a company source said on Wednesday.The Anglo-Dutch company slashed its 2020 spending plans by a fifth as measures to halt the spread of the virus led to an unprecedented drop in oil demand and sent oil prices to their lowest in two decades.As a result of this, the source said..