Added better support for static build

Edited the CMake files to better support a static build. I haven't tested on Linux nor MacOS.

Fixed the output extension on windows (would build as a .dll when BUILD_SHARED_LIBS was off)
Fixed the samples not compiling when BUILD_SHARED_LIBS is OFF due to BEARLIB_TERMINAL_STATIC_BUILD not defined, thus causing linker errors
Made the dependency libraries also copy to the output folder for use when statically compiling.

cfyzium / bearlibterminal