Chainer utils use deprecated methods

[Masaya Suzuki]

(Related to #7)
These methods use deprecated methods when using Chainer v1.24.0:

deep-crf/deepcrf/util_chainer.py

Lines 44 to 49 in ee2880c

 def my_cuda_get_device(cuda, device_id): 
     if version < '2.0': 
         cuda.get_device(device_id).use() 
     else: 
         # v2.0 
         cuda.get_device_from_id(device_id).use() 

deep-crf/deepcrf/util_chainer.py

Lines 52 to 57 in ee2880c

 def my_cleargrads(net): 
     if version < '2.0': 
         net.zerograds() 
     else: 
         # v2.0 
         net.cleargrads()