Splits the IconLabel widget header into a header and source file. The
source uses the moc_icon-label include to prevent the moc from being
included in the global mocs_compilation (as described in 5eb04cd).
For custom types to become usable as QVariants they not only need to
be declared as meta types, but also need to have appropriate stream
operators declared.
These declarations (both of the meta type itself, which provides a
static meta type ID getter via the macro, as well as the operators)
need to be visible to the compiler in any compilation unit where they
might be used in their QVariant form, otherwise the templates will
be incomplete.
A blanket include of "qt-wrappers.hpp" in "OBSBasic.hpp" is not the
most subtle fix, but it's necessary to ensure that the meta types
are always "complete". Putting both declarations in the qt-wrappers
header (instead of splitting them up) ensures that (as the classes
themselves are declared in "obs.hpp", which is included by
"qt-wrappers.hpp", and thus qt-wrappers can provide a complete class.
When a source file contains an explicit include with a filename
following the "moc_<actual-filename>.cpp" pattern, then CMake's
AUTOMOC generation tool will recognize the matching pair and generate
the replacement header file and add the required include directory
entries.
For all files which do contain Q_OBJECT or similar declarations but do
not have an explicit include directive, the global mocs_compilation.cpp
file will still be generated (which groups all "missing" generated
headers).
The larger this global file is, the more expensive incremental
compilation will be as this file (and all its contained generated
headers) will be re-generated regardless of whether actual changes
occurred.
