Merge pull request #994 from lakkatv/lakka

(GLUI) Allow use of non monospaced fonts
(gl_font_renderer_t) Add get_glyph() function pointer
Merge pull request #995 from heuripedes/master

(gl_font_renderer_t) Add get_glyph() function pointer
(gl_raster_font.c) Fix warning
Merge pull request #997 from heuripedes/master

(gl_raster_font.c) Fix warning
Merge pull request #996 from lakkatv/lakka

GLUI) Use two column layout
(GLUI) Adapt to font size