Log Message:
Add options.mk to utilise the options framework, enabling the user to build
with the alsa, opengl, png, pulseaudio, xrandr, xvideo, and zlib
PKG_OPTIONS. png, xrandr, xvideo, and zlib are enabled by default, since
those are the package's defaults. This relocates libXv from Makefile and
moves the disabling of OpenGL (which i can't see a reason why it is/was
disabled) to options.mk. Add msgmerge, xgettext, and perl to USE_TOOLS.
Set LICENSE to gnu-lgpl-v2.1, which is reflected on HOMEPAGE, but code also
includes gnu-gpl-v2 code, so add that too just to be safe. Bump PKGREVISION