Subject to the provisions of subsection (2) of section twelve and subsection (1) of section sixty-eight of this Act in particular, and to any other provision of this Act which otherwise expressly provides, nothing in this Act shall prejudicially affect any power, right or remedy of a landlord, tenant or other person, vested in or exercisable by him by virtue of any other Act or law, or under any custom of the country, or otherwise, in respect of a lease or other contract, or of any improvements, deteriorations, away-going crops, fixtures, tax, rate, teind, rent or other thing.