Date Cycle; setting the Cycle Mnemonic now handles larger range of descriptions

Setting the Mnemonic of a Date Cycle now handles more scenarios. Note that the Mnemonic is not designed to handle plain English text.

For example, "Every End of Month" is now converted to "e". Previously the text "Every" caused the date cycle to fail to convert.

Other Text, such as "Half Yearly", "Bimonthly" and "Four Weekly" are also now handled.