This patch introduces tvgTvgHelper.h file that contains base definitions used
for .tvg loader and saver modules. Indicators, flags and sizes are defined
and base tvgBlock struct is declared here.
'tvgTvgHelper.h' file is essential only for .tvg loader/saver module and it
doesn't affect any other file. Loader and saver modules itself are introduced
in other, further patches.
.tvg is a binary file format designed for saving/restoring the scene content.
It allows to save scenes and reuse them in other apps or to restore state of
the application.