Updates to HAL

[dmirota]

Improvements in file reading and build

[crheckman]

@mcguire-steve: could you please test this in linux? I'll test in Mac.

@dmirota thank you for your PR!

[mcguire-steve]

One thing I would like to ask is that the 'CONFIG' option to find_package be removed. By including this option, one explicitly requires the system to provide a .cmake file (such as protobufConfig.cmake), instead of allowing CMake to use any of a system module (under e.g. /usr/share/cmake-3.16/Modules), a user module (under HAL/cmake_modules), or a package config file (perhaps under /usr/lib/cmake//Config.cmake

Requiring CONFIG requires standardized names of libraries, as well as package management to provide the Config.cmake file. The addition / use of user modules allows for different flavors of systems to be supported.

To test this, I had to:

1. Incorporate harel's feature/opencv4 branch
2. Remove glog::glog from line 61 - unclear why this is necessary instead of the find_package constants
3. Remove the CONFIG directive from glog and protobuf
4. Change the caps for glog to GLog, so that the FindGLog module is called
5. Capitalize Protobuf (line 27) to use the CMake system FindProtobuf module
6. Disabling certain drivers that haven't yet been updated (OpenNI2, Freenect2)

[dmirota]

@mcguire-steve Note see:
https://github.com/dmirota/vicalib/blob/master/meta_build/Projects/HAL.cmake
https://github.com/dmirota/vicalib/blob/master/meta_build/Projects/GLog.cmake
https://github.com/dmirota/vicalib/blob/master/meta_build/Projects/protobuf.cmake
https://github.com/dmirota/vicalib/blob/master/meta_build/Projects/OpenCV.cmake
for how the dependencies are configured. I'm working on getting this running on Travis.

[crheckman]

@mcguire-steve have you had any more success on this? The Mac side is still taking time but I'm getting to the bottom of it.

[dmirota]

@crheckman let me know if there is anything I could help explain. I'm happy to walk-through the build with you.