v2.1.1

Minor changes: not checking for "too large values" anymore, it is the user's responsibility to check if values are overflowing. Program is limited by Chrolis API (time in us is accepted as UInt32). "Too large" check only protected user for small range of issues: when the value N modulo max UInt32 value is between the too large range L and the UInt32 maximum value M: N%(M+1) in [L, M]. So overflow would still be possible without exception.