extract_features.cpp compile fixes

[marc40000]

3 Things:

• snprintf => _snprintf
• typedef unsigned int uint; at the top
• shared_ptr to boost::shared_ptr

Maybe I should check out how to do pull requests ...

[niuzhiheng]

Thank you for your feedback. I am very glad to receive your PR.

Please refer to the paragraph of Shelhamer's “life of a branch in four acts” from official readme to see how you may do that.

[niuzhiheng]

Solved in abfee75a2494092e149489a29fc8f8147ec38b38

[marc40000]

Ok. If there is a next time I'll figure out the pr before posting an issue ;)