Debugger UI Refactor (React Library)

[ioedeveloper]

Closes #399

[yann300]

Each time the slider is moved, line 9 get hit 1 time and line 13 2 times.
even if if (value === state.currentValue) return helps, that may be useful to check if that may cause performance issue in the stack.

[yann300]

An error is thrown while unfolding an item from the treeview.
Also the way it is formmatted doesn't seem to be accurate

[yann300]

^ that seems to be fixed

[yann300]

debugging test.set(12) (see bottom) gives a wrong state when being inside the test2.set(12) the value p should be 34 but it displays 8

contract test {
    uint p;
    test2 t;
    constructor () public {
        t = new test2();
        t.set(34);
    }
    
    function set(uint _p) public {
        p = _p;
        t.set(12);
    }
}

contract test2 {
    uint p;
    function set(uint _p) public {
        p = _p;
    }
}

[yann300]

^ please scratch that... the issue exists in remix-alpha already

[yann300]

This seems not use in this PR, is this still needed to keep it?