[ros2][Windows] Include Boost to fix Windows build

[jnoyola]

Addresses #289

The Boost dependency already exists, but it's failing the Windows build because it must be explicit.

This comment explains more of the long-term plan to remove this dependency:

I added a shim to rcpputils to remove the boost/endian dependency (https://github.com/ros2/rcpputils/blob/master/include/rcpputils/endian.hpp), we could potentially get that backported to dashing to completely remove boost dependency from C++, but there won't be any python until pybind11 lands.

[jnoyola]

I could use some help understanding this build failure. As far as I can tell, it looks like it just timed out when doing an apt-get install.

[seanyen]

cc @mjcarroll I confirmed it is still an issue on Windows. The build error will manifest as below:

F:\workspace\ros2_ws\src\vision_opencv\cv_bridge\src\cv_bridge.cpp(39,10): fatal error C1083: Cannot open include file: 'boost/endian/conversion.hpp': No such file or directory [F:\workspace\ros2_ws\build\cv_bridge\src\cv_bridge.vcxproj]

After applying this fix, the build can run successfully.

[mjcarroll]

Thanks for the contribution!