Applied the changes which somehow vanished during my last merge. Thanks goes
to Marci for noticing this. In detail:
- added amsmath and amssymb latex packages for latex documentation
- src/demo is also scanned for doxygen input files

BINARIES = bfs_test min_cost_flow

INCLUDEDIRS= -I../.. -I.. -I../{athos,klao,marci,jacint,alpar,johanna,akos} 

include ../makefile