Group liblove and lovedep projects in Visual Studio

[learn-more]

This is the end result:

[slime73]

From the linux build failure:

CMake Error at extra/cmake/LoveMacros.cmake:11 (get_target_property):
  get_target_property() called with non-existent target "lua51".
Call Stack (most recent call first):
  CMakeLists.txt:1926 (love_group_projects)

-- Configuring incomplete, errors occurred!

CMake Error at extra/cmake/LoveMacros.cmake:13 (if):
  if given arguments:

    "STREQUAL" "INTERFACE_LIBRARY"

  Unknown arguments specified

[learn-more]

@slime73 This should now be fixed

[slime73]

This seems ok to me, but I'd like someone with more cmake experience to look at it as well.

[bartbes]

Would it make sense to also separate out the 3rd-party (love_3p) targets?

[learn-more]

Would it make sense to also separate out the 3rd-party (love_3p) targets?

If you prefer that I can group those in a sub-folder as well.
Any suggestions for the name?
I'd think something like lovedep/third-party or so?