MultiColored text does not use kerning

[BNNorman]

When calculating the length of a text message the code calls the relevant method for each font to find out the length of the message in pixels in order to create an image onto which the text is rendered before being sent to the panel.

The code handles multicolored text character by character and uses the individual character widths to place the characters. Unfortunately this results in the string being too long.

To solve the problem Multi-colored text needs to use kerning.

[BNNorman]

OPENCV/Font.py and PILFONT/Font.py have been updated to render multicolored text with the correct kerning so that plain colored text and multicolored will be of the same size.