add UpdatePage() method for SMSPage class

[Blu3wolf]

The method should take arrays of strings as parameters, and feed those strings sequentially into UpdateOSB() and UpdateINVSt() methods with a foreach loop.

[Blu3wolf]

This is connected to the DisplayForm method ValidateInput, which will need refactoring. Specifically, it has no way to handle multiline input.

[Blu3wolf]

need to be smart about how data is presented/stored. To that end, it might be worth looking into having a separate label for each line in the display. Information needs to be stored separately to the string, and have the string generated on demand from the stored information. Updating the display should be done so that it works out for itself what lines need to be displayed.