Switch from 0.5.7 to 0.6 and update libtool versioning to note incompatibilty

Add razor_install_prefix_iterator_create()

Fix memory leak

Add basic checks for rpm file format

Add missing files

Fix multiple memory allocation problems (found with valgrind)

Add low-level dump command to aid debugging

Add facility to specify razor command when running tests.

This makes it easy to run under eg., valgrind as:

./details "libtool --mode=execute valgrind --leak-check=yes ../src/razor"

Support downloading from local repository even without libcurl

Using the --url option of the razor executable, it is possible
to specify a yum repository on the local machine (eg., on installation
media) and import from there, eg.,:

C> razor --url file:///d:/ import-yum

This will be handled by libcurl if available but if not, an internal
copy routine will be used.

Note that if Microsoft's KTM implementation of atomic transactions is
used, then the current directory must support atomic transactions
(also improve error messages for this, and other, cases).

Only export symbols starting with razor_ in dynamic library.

Apart from being good practice to avoid clashes with higher-level
libraries and the application, this also fixes an obscure bug: The
gnulib library is used both by librazor (the dynamic library) and
by razor (the executable). In doing so, we want to have two separate
copies of the library despite the code duplication this involves.
Without the explicit limit to export only razor_ symbols, the razor
executable under mingw64 was picking up the getopt_long function
from librazor and the optind variable from libgnu which meant that
it did not see optind changing. Hiding librazor's copy of getopt
causes the linker to find libgnu's copy and everything works.

Note that under mingw librazor-#.dll still contains undocumented
(private) razor_ symbols but these will do no harm as long as nobody
tries to use them.