@debug decorator to make it easier to use dropin debugger
@debug decorator to make it easier to use dropin debugger

Summary:
Now it takes two lines to get drop-in debugger: import it and
then decorate your function. Also got rid of enable / disable logic as
it doesn't seem usefull.

We can also try to enable this by default for our tests when running
locally as a next step.

Reviewed By: bwasti

Differential Revision: D4444299

fbshipit-source-id: 6e2006945d8ad640685b1017ca1bd63054728908

xzturn/caffe2,sf-wind/caffe2,davinwang/caffe2,bwasti/caffe2,caffe2/caffe2,bwasti/caffe2,davinwang/caffe2,sf-wind/caffe2,davinwang/caffe2,Yangqing/caffe2,sf-wind/caffe2,pietern/caffe2,xzturn/caffe2,Yangqing/caffe2,bwasti/caffe2,davinwang/caffe2,sf-wind/caffe2,Yangqing/caffe2,pietern/caffe2,xzturn/caffe2,xzturn/caffe2,pietern/caffe2,Yangqing/caffe2,sf-wind/caffe2,pietern/caffe2,bwasti/caffe2,davinwang/caffe2,pietern/caffe2,bwasti/caffe2,Yangqing/caffe2,xzturn/caffe2