Fixed some compilation errors and unit test failure

* link in eigen3 library to vl_test target
* Add new "template class SimpleWriteSyncGuard<Entry<long long>>;", since build will fail on OSX
* Add template keyboard to data<T>(0).Get() (otherwise this fails on OSX)
* Fix unit test in sdk_test.cc

Tested build and unit test run on OSX and Ubuntu with no issues

* Add edges to graph. Add squeezenet to mock data.

* rm json

* rm pb files and add links to them

* Add edges to graph. Add squeezenet to mock data.

rm json

rm pb files and add links to them

* added download script

* typo

Merge branch 'develop' of github.com:PaddlePaddle/VisualDL into feature/add_image_component-add_server_test

just a trick to store int8 in protobuf

should limit the maximum image shape latter

support onnx as graph data format and add related API