Add support for namespaces.

For details of the new feature, see
https://github.com/luarocks/luarocks/wiki/Namespaces

This ended up being a huge commit because of some major refactoring
motivated by the new feature:

* new modules for some object types:
  * `luarocks.queries` - all functions that look for rocks in local or
    remote repositories now use objects constructed by this module:
    query objects contain the name, namespace and query constraints.
    Dependencies in a rockspec are also stored as query objects.
  * `luarocks.results` - all individual results produces from queries
    are returned in this format: result objects contain the name,
    namespace, version, arch and repo.
* the `results` object was renamed to `result_tree`, to better
  reflect that it is not an array of `result` objects.
* `luarocks.vers` was removed, its functionality was moved to better locations.

Specifically on namespaces:

* Commands that take a rock `name` can now take `namespace/name`
  (and alternately `--flags=namespace` so that URLs can be
  also installed with a nominal namespace).
* Rocks installed from a namespace now create a `rock_namespace`
  file alongside `rock_manifest`, which is used when matching
  namespaced dependencies against locally-installed rocks.
* Using namespaced dependencies in a rockspec, requires
  `rockspec_format = "3.0"`.
* Tests under the `#namespaces` hashtag, all using a local repository.

1 files changed, 2 insertions, 1 deletions

diff --git a/spec/util/mock-server.lua b/spec/util/mock-server.lua
index 77d32927..30586c98 100644
--- a/spec/util/mock-server.lua
+++ b/spec/util/mock-server.lua
@@ -70,7 +70,8 @@ server:add_resource("/file/{name:[^/]+}", {
       path = "/",
       produces = "text/plain",
       handler = function(query, name)
-         local fd = io.open("../spec/fixtures/"..name, "r")
+         local basedir = arg[1] or "../spec/fixtures"
+         local fd = io.open(basedir .. "/" .. name, "r")
          if not fd then
             return restserver.response():status(404)
          end