Removes a constraint that the fancy string drawing function fl_draw() is limited to 1024 chars/line
that blocked a user of the Fl_Browser widget (see "fl_draw MAXBUF limit" in fltk.coredev).

Also, removed a useless computation in string expansion that checked for valid UTF-8 sequences:
the point is that a valid UTF-8 sequence for a non-ascii char contains no ascii char,
thus no tab, space, control, & or @ we want to process differently. 
Also, invalid UTF-8 sequences are copied unchanged by this procedure.
Therefore, checking for tab, space, control, & or @, and copying the byte otherwise, is enough.


git-svn-id: http://seriss.com/public/fltk/fltk/branches/branch-1.3@10123 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
Minor reformatting to follow the coding style of the CMP.

git-svn-id: http://seriss.com/public/fltk/fltk/branches/branch-1.3@10124 ea41ed52-d2ee-0310-a9c1-e6b18d33e121