袖珍计算器

v3.0.13: put change of rounding/fixed decimal places in recent history, add a larger font size to recent history and help.v3.0.12: fix layout for 7" tabs to fill screen correctly, display fractions symmetrically on all devicesv3.0.11: If a result is too long to fit in the display at normal size, the text size will be reduced to squeeze it in.v3.0.10: Calculator layout changed to fill screen. Title bar will be shown on all but smallest devices.