make justifyFont() return the actual justification

so we can apply it manually
apply justification in renderLine()

rather than directly in justifyFont()

LATER: think about using "FTLayout" for doing the layout
removed unused code
use two font-pointers, and make m_font only a proxy to them

oho...this commit is broken (cannot split into two separate commits anymore)
use renderLine() rather than our own render()

so we can re-use the justification code in TextBase
set m_font to the font returned by makeFont()
update font when aliasing is changed
make "antialias" an alias for "alias"
aliased/anti-aliased [text3d]
check whether font exists before checking for errors
remove upper precision clamp

this is really a bug in FTGL and should be fixed there
(see Debian Bug #744756)
invalidate m_font when fonts are freed
some additional Error checking when setting FaceSize

don't know whether this will do anything...
moving m_dist factor from makeLineDit() to render()
make line-distance independent of m_precision
updating copyright date
added splitscreen example
Merge branch 'text'