changelog:
1.42:
fix 1 斗(田) = 674.5 平方米 instead of 674 平方米

1.41:
-minor bug fix

1.4:
-added pressure conversion
-restore configuration of last usage

1.3:
-added currency conversion
-added unit stone(uk) in weight
-added unit K in temperature

1.2:
-added temperature conversion
-added some units in weight

1.1:
-first release version on play store