Function numberTest

Checks if t is not a number or within specified range. Returns [false, reason:string] if invalid or [true] if valid.

Alternatives: integerTest for additional integer check, percentTest for percentage-range.

• (empty, default): must be a number type and not NaN.
• finite: must be a number, not NaN and not infinite
• positive: must be at least zero
• negative: must be zero or lower
• aboveZero: must be above zero
• belowZero: must be below zero
• percentage: must be within 0-1, inclusive
• nonZero: can be anything except zero
• bipolar: can be -1 to 1, inclusive