Implement new Number assertions:

• IsInt - succeeds if number is signed or unsigned integer (does not have fractional part)
• IsUint - succeeds if number is unsigned integer (does not have fractional part and is >= 0)
• IsFloat - succeeds if number is not integer (have fractional part, is opposite to IsInt)
• IsNan - succeeds if number is NaN

Each of them, except IsNan, should have optional argument bits which defines maximum allowed bitness for the number, e.g. IsInt(32) means that the number should fit in 32-bit signed integer. See String.AsNumber for en example of optional argument.

For every assertion, also add negative version (NotInt, NotUint, etc).

Each assertion should have documentation comment with example and be covered by unit tests. Don't forget to cover corner cases like NaN, inf, etc.