README

A README file for my first serious iOS project.
It is yet another science calculator.
--By Richard Dong

## Log
2012-02-26 Start coding the UI.
2012-02-27 Create a git repository.
2012-02-28 Draw button images.
    For some devices, default fonts may be replaced.
    So I may have to use images for all buttons.
2012-02-29 Layout buttons.
    Still some button images to draw.
    Move images to a single directory.
2012-03-02 Draw button images and add screen.
    Button images have to be cached.
    I will make a cache for them.
2012-03-04 Add image-pool for buttons.
    Use tag for buttons.
    Add LED indicators.
    I don't like the indicators.
2012-03-05 Localize display name.
    Add launch image and app icon.
    Add three20 as sub-module.
2012-03-06 Add View Controller for Menu.
    I shall add User Config as well.
2012-03-07 Add Settings bundle.
2012-03-10 Change AddButton Macro.
    Change macro to const vars.
2012-03-12 Finish 'shift' and 'hyp' buttons.
    I want to change the corresponding button appearance.
2012-03-17 Add labels for LED display.
    Start coding for classis calculator.
2012-03-21 Finish number formatter.
    Add Delete to number input logic.
2012-03-22 Add 'answer' state.
    The logic to display the expression is complicated.
    Use 'isnan' in std c lib.
2012-03-23 Add 'error' state.
2012-03-26 Add logic for operators with two operands.
    Add combination computation.
2012-03-27 Add logic for parentheses.
	Finish code for '=' button.
2012-03-28 Display expression.
2012-04-01 Adding functions.
	Thinking about revise the UI.
2012-04-09 Rewrite UI.
    Give up 'Line Mode'.
2012-04-19 Refine button pad transition.
    Refine expression display with functions.
2012-04-23 Finish M+/M-/MR/MC.
    Finish feedInputNumber method.
2012-04-26 Finish const PI/E,rand.

## Todo
    >> ans button.
	>> F-E button.