Move files from inc/ into src/

  for d in src/*
  do
    test -e $d/FILES || continue
    for f in $(cat $d/FILES)
    do
      test -e inc/$f && git mv inc/$f $d
    done
  done
Recursively compute INCLUDE_DIRECTORIES needed by each module
Add missing dependencies between OCC modules
Fix compilation with precompiled headers
Merge pull request #367 from tpaviot/review/move-header-files-into-src-take2

Move duplicated header files from inc/ back into src/