liblibo: fixes and improvements for liblibreoffice

fixes for liblibreoffice-Impl (init.cxx): determine outputfilter from file
suffix if no filter is provided; ensure that url provided to
XStorable.storeToUrl is really an url; improved error handling

small improvements in somektest/libtest.cxx: output times required for init,
load and save.

Change-Id: Ic8b2c0d34cbeae3250c43cac02690e6ec1954ed7
liblibo: make liblibreoffice static as it should be.

The whole purpose of this tiny library is to break dependencies,
so requiring it in our library path is a bit silly.

Change-Id: Ie0e000b97db87afd57f693e19341eadf97323335
liblibo: share crude URL absolutization, and clean.

Change-Id: I559eac8626a011644f68f8391631447f15c643eb
liblibo: improve the libtest sample app.

Add command-line help, validate arguments more, better error reporting.

Change-Id: Ia092895d0d116b003bb6c2a252f68ae9b6ba6d35