[ci/appveyor] removed 32 bit from build matrix
[ci/appveyor] removed 32 bit from build matrix

rmcgibbo/mdtraj,mattwthompson/mdtraj,dwhswenson/mdtraj,dwhswenson/mdtraj,jchodera/mdtraj,mattwthompson/mdtraj,mattwthompson/mdtraj,jchodera/mdtraj,gph82/mdtraj,gph82/mdtraj,rmcgibbo/mdtraj,mattwthompson/mdtraj,mdtraj/mdtraj,mdtraj/mdtraj,mdtraj/mdtraj,dwhswenson/mdtraj,jchodera/mdtraj,rmcgibbo/mdtraj,jchodera/mdtraj,gph82/mdtraj