[Libguestfs] [PATCH 00/12] Refactor utility functions.

This turned out to be rather more involved than I thought. We have lots of utility functions, spread all over the repository, with not a lot of structure. This moves many of them under common/ and structures them so there are clear dependencies. This doesn't complete the job by any means. Other items I had on my to-do list for this change were: - Split up mllib/common_utils into: - bindings around common/options to common/mloptions - util functions (such as error handling) used by the virt-* OCaml utilities to common/mltools (Tools_utils) - Move mllib/uri* -> common/mloptions - Other mllib/ modules used only by tools can also be moved to common/mltools, eg. curl, JSON, regedit, ... Rich.