Allow font size as parameter to AddFontDefault

[drewish]

I'd like to use the default font but multiply the size so it works with retina/high resolution screens. I'm curious what people think about adding that as a parameter. AddFontDefault already takes an optional ImFontConfig param but I'm not seeing it used anywhere. I don't know if it would make sense to try pass the font size in via the config (which looks like it would be overwritten during the call to AddFontFromMemoryCompressedBase85TTF) or just add a new parameter with a default value of 13 to preserve the current behavior.

I'm happy to open up a PR once there's an idea of the best path forward.

[colesnicov]

Have you tried looking for?

#407
#658

[ocornut]

@drewish please use the workaround linked above. If you are trying to solve Hi-DPI support then it should eventually be handled more naturally by the library and I'd prefer not encouraging people to rescale the default font (which isn't really meant to be rescaled).

[drewish]

Ah apologies I'd definitely missed those. That makes sense to me.