Editing Amount is Done

Transaction object got Notify abilities so the xaml binding will work
both ways.

The Amount Editing style is done.
When the amount is negative, the color is red but there is no negative
sign.
Just when the TextBox get keyboard focus, the negative sign appear.
After than the Amount editing is just as you expect.

Description Editing is now working with Notify as well.

VisualItemTransactionConverter  Moved to a new file named
VisualConvertersAndUtils that contains also MyFormating class that we
are going to work with in the future.

The main unintuitive change is that Transaction object now got an
RealAmount Property that return negative amount, If type is Outcome.
The setter for this property changes both the type and the amount, as
long the original type is not Transfare.
This property is for the binding with the txtAmount TextBox so that the
convertor (For the binding) would get the real amount and would know
whether to color the number or now.

The one exception to the rule of binding is when the txtAmount got
keyboard focus. than we are actively changing the Text property of the
txtAmount element and adding to it the negative sign (-) if we should.
That seems to not harming the binding process.