documentation generator should show needed so files

[luxe]

Part of generating the documentation should be running ldd and showing the .so files that are expected. It would be nice to do this through a library call instead of running ldd directly. That way we can show it in the documentation in a nicer format than:

	linux-vdso.so.1 (0x00007ffe1a5f3000)
	libgmpxx.so.4 => /usr/lib/x86_64-linux-gnu/libgmpxx.so.4 (0x00007f81591b0000)
	libgmp.so.10 => /usr/lib/x86_64-linux-gnu/libgmp.so.10 (0x00007f8158f2f000)
	libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f8158b91000)
	libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f8158972000)
	libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f815876e000)
	libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f815837d000)
	libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007f8157ff4000)
	libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f8157ddc000)
	/lib64/ld-linux-x86-64.so.2 (0x00007f81593b6000)

[luxe]

and basically a lookup table, that says:
you can get this if you apt-get install x

[luxe]

good enough. I added a note to use apt-file search <file> for finding packages. That's for ubuntu only, but a good start.