Cleaning up Dub/Dmd builds

[WhatMeWorry via Digitalmars-d-learn]

Just some basic questions regarding Dub projects with GitHub. I'm 
just getting
my toes wet with GitHub so these might be pretty naive questions.

I've got about 35 mini dub projects where each project holds an 
OpenGL tutorial.
like so:


01_01_hello_window
     .dub
         build
            
application-$DFLAGS-windows-x86_64-dmd_2071-090A2D44A9209535339D8167E6A96BA6"
            o  o  o
            
application-$DFLAGS-windows-x86_64-dmd_2071-D8ED32593AF993350341F03512FE4A7C"
         dub.json
      source
          (all my .d files)
      01_01_hello_window.exe
      dub.sdl
      dub.selections.json
01_02_textures
     .dub
          build
       (etc.)

When I try to upload these files to my new repo, GitHub 
(rightfully so) complains that
I have too many files. Since I'm using sdl and not json, can I 
safely delete all the files
that pertain to json?  Can I do this some way at the command line?

Also, I have tons of empty folders with cryptic names like
"application-$DFLAGS-windows-x86_64-dmd_2071-D8ED32593AF993350341F03512FE4A7C" above.
Is there some way to suppress these from even being created?

Finally, is it problematic to have so many little dub folders?  
Should I have organized
things in a different (better) manner?

Thanks.