Add MIN_LINE_SIZE property

Add MIN_LINE_SIZE property

Users want to set the line size in multi-line.
We have a lineSpacing property which allows us to set the spacing of the lines.

However, the user wants to achieve a similar effect by setting the size of the line, not lineSpacing.

Change-Id: Ia96e1875e90454a3269d2ad853d3c4e20ce66ae9