Extend number recognition

[rolfkleef]

Problem in spreadsheets2iati: mix of using point and comma for decimals and thousands:

• 100.000
• 100,000

Add heuristics to recognise the format used:

• Point and comma both used? First is thousands, second/last is decimals.
• Point or comma with three following digits as the end? Thousands
• Point or comma with two digits as the end? Decimals
• etc.

[rolfkleef]

need to add a try-catch or similar in case a format cannot be converted, to prevent a fatal error in the conversion.

[rolfkleef]

prevent fatal error done in https://github.com/data4development/iati-workbench/commit/ffe3fc32c5c9677df3e0c53abce1be602d702f18