Possibility to limit values a positive integers

[karilint]

For example, Locality > Climate > Estimate of annual precipitation (mm)

• must be a positive integer value
• Now we can set ['Estimate of annual precipitation (mm)', textField('estimate_precip', 'number')],
• It could be something like: ['Estimate of annual precipitation (mm)', textField('estimate_precip', 'positive_integer')],
• we could even have additional limitations like between 0-100