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, 8 insertions, 0 deletions

diff --git a/spec/doc_spec.lua b/spec/doc_spec.lua
index 5f503af2..6d91fc00 100644
--- a/spec/doc_spec.lua
+++ b/spec/doc_spec.lua
@@ -38,6 +38,14 @@ describe("LuaRocks doc tests #blackbox #b_doc", function()
          assert.is.truthy(output:find("Local documentation directory not found"))
       end)
    end)
+
+   describe("#namespaces", function()
+      it("retrieves docs for a namespaced package from the command-line", function()
+         assert(run.luarocks_bool("build a_user/a_rock --server=" .. testing_paths.fixtures_dir .. "/a_repo" ))
+         assert(run.luarocks_bool("build a_rock --keep --server=" .. testing_paths.fixtures_dir .. "/a_repo" ))
+         assert.match("a_rock 2.0", run.luarocks("doc a_user/a_rock"))
+      end)
+   end)
    
    describe("LuaRocks doc tests with flags", function()
       it("LuaRocks doc of installed luarepl", function()