Change-Id: Ia5358f88129b5c2e2a2653b1d85c168b80d797b3

* Fix ParameterAttribute for img_conv_layer, tensor_layer, crf_layer, crf_decoding_layer.

Change-Id: Ic24e4bc1f9d5e03bf35058b49a54c78caf7e97a8

ISSUE=4619881 

git-svn-id: https://svn.baidu.com/idl/trunk/paddle@1502 1ad973e4-5ce8-4261-8a94-b56d1f490c56

ISSUE=4612671

git-svn-id: https://svn.baidu.com/idl/trunk/paddle@1501 1ad973e4-5ce8-4261-8a94-b56d1f490c56

ISSUE=4612433 

git-svn-id: https://svn.baidu.com/idl/trunk/paddle@1476 1ad973e4-5ce8-4261-8a94-b56d1f490c56

ISSUE=4611081


git-svn-id: https://svn.baidu.com/idl/trunk/paddle@1475 1ad973e4-5ce8-4261-8a94-b56d1f490c56

Also fix link in quick_start

ISSUE=4611783



git-svn-id: https://svn.baidu.com/idl/trunk/paddle@1474 1ad973e4-5ce8-4261-8a94-b56d1f490c56

ISSUE=4611579

git-svn-id: https://svn.baidu.com/idl/trunk/paddle@1473 1ad973e4-5ce8-4261-8a94-b56d1f490c56

ISSUE=4599577


git-svn-id: https://svn.baidu.com/idl/trunk/paddle@1440 1ad973e4-5ce8-4261-8a94-b56d1f490c56

ISSUE=4592807 

git-svn-id: https://svn.baidu.com/idl/trunk/paddle@1423 1ad973e4-5ce8-4261-8a94-b56d1f490c56

ISSUE=4539687

git-svn-id: https://svn.baidu.com/idl/trunk/paddle@1422 1ad973e4-5ce8-4261-8a94-b56d1f490c56

ISSUE=4584581 

git-svn-id: https://svn.baidu.com/idl/trunk/paddle@1413 1ad973e4-5ce8-4261-8a94-b56d1f490c56

Also add some comments for cost layers.
ISSUE=4580653

git-svn-id: https://svn.baidu.com/idl/trunk/paddle@1410 1ad973e4-5ce8-4261-8a94-b56d1f490c56

ISSUE=4586495

git-svn-id: https://svn.baidu.com/idl/trunk/paddle@1408 1ad973e4-5ce8-4261-8a94-b56d1f490c56