[Libreoffice] new configure options to make branding easier

[Andras Timar]

Hi,

I've just pushed a few more configure options to master in order to
make branding LibreOffice easier.

There are 3 elements that can be configured now.

About bitmap:
--with-about-bitmap
We already had this this option.

Intro bitmap aka splash screen:
--with-intro-bitmap
We already had this this option, but there are more to configure from
now on. It is possible to modify the color, the size, the position and
the frame color of progress bar.
--with-intro-progressbar-color
--with-intro-progressbar-size
--with-intro-progressbar-position
--with-intro-progressbar-frame-color

Start center background bitmaps:
--with-startcenter-left-bitmap
--with-startcenter-right-bitmap
--with-startcenter-rtl-left-bitmap
--with-startcenter-rtl-right-bitmap
--with-startcenter-space-bitmap

Best regards,
Andras