Update to Coyote's software run-time

[bo3z]

The recent PR (#185) adds support for installing Coyote's software run-time as a system-wide library, making it easier to include in large projects. Alternatively, it's still possible to include Coyote as a submodule (sub-directory), without installing a system-wide library.

As a consequence, FindCoyoteSW.cmake has been deprecated in favour of add_subdirectory and find_package macros in CMake. CMake configurations relying on FindCoyoteSW.cmake will continue working as normal; however, they should migrate to the new code structure.

More details about how to compile the code can be found in the updated README: https://github.com/fpgasystems/Coyote/tree/master/sw#using-the-software