This chapter shall not be construed as abating any action now pending under or by virtue of prior existing subdivision regulations, or as discontinuing, abating, modifying, or altering any penalty accruing or about to accrue, or as affecting the liability of any person, firm, or corporation, or as waiving any right of the city under any section or provision existing at the time of adoption of this chapter, or as vacating or annulling any rights obtained by any person, firm, or corporation, by lawful action of the city, except it shall be expressly provided for in this chapter.