Remove some debug prints from depsolver.

Add read-only open function for razor_root and support --root in rpm wrapper.

Add --initdb support for rpm wrapper.

Move razor root code to its own file.

Add librazor.a to Makefile to make it clearer what is core razor.

Introduce struct razor_root.

This object encapsulates the directory layout and locking protocol for
a razor install root.

Make yum url overridable by environment variable YUM_URL.

Rewrite depsolver to use a series of passes over all packages.

The big change is that we follow one step of the depedency chain for
each package to resolve in each iteration, and repeat until there are
no more possible moves. In contrast the old depsolver would try to
follow the dependency chain completely for one package at a time.

This new approach is simpler and faster, and at the same time more
roboust. Instead of knowing how one newly installed package may
affect other packages (obsoleting, pulling in new packages etc), the
new algorithm just looks at the total list of requires, provides,
obsoletes and conflicts after installing new packages.

WIP patch for seperate files for filelists and package details

Use a seperate string pool for package details