.obj files conflict

[Nick Atamas]

I find that .obj files conflict when I use the -od flag to redirect
intermediate output to a directory. Shouldn't obj files get the name of their
package? So, sdl.timer.obj instead of just timer.obj.

e.g.

c:\proj> bud -odbin src/main.d
[proj]
  |--[bin]
  \--[src]
      |--[A]
      |  \--Timer.d
      |
      |--[sdl]
      |   \--timer.d
      |
      \--main.d  #imports and uses both timers


This will cause a linker error because bin/Timer.obj will be overwritten by
bin/timer.obj.

This isn't just a problem on windows. If we had both lower-case names as in
A/timer.d and sdl/timer.d, there would still be a linker error.