Fixes problem with subdirs and 'develop'. Documents package urls.

readme.markdown

@@ -183,8 +183,17 @@ the current working directory. This can be useful for developers who are testing
 locally their ``.nimble`` files before submitting them to the official package
 list. See the [Creating Packages](#creating-packages) section for more info on this.
 
-A URL to a repository can also be specified, Nimble will automatically detect
-the type of the repository that the url points to and install it.
+#### Package URLs
+
+A valid URL to a Git or Merurial repository can also be specified, Nimble will
+automatically detect the type of the repository that the url points to and
+install it.
+
+For repositories containing the Nimble package in a subdirectory, you can
+instruct Nimble about the location of your package using the ``?subdir=<path>``
+query parameter. For example:
+
+    $ nimble install https://github.com/nimble-test/multi?subdir=alpha
 
 ### nimble develop
 
@@ -206,6 +215,9 @@ current working directory.
 The ``jester`` package will be cloned into ``./jester`` and it will be linked
 to your installation directory.
 
+Just as with the ``install`` command, a package URL may also be specified
+instead of a name.
+
 ### nimble uninstall
 
 The ``uninstall`` command will remove an installed package. Attempting to remove

src/nimble.nim

@@ -1012,7 +1012,7 @@ proc develop(options: Options) =
       let (meth, url, metadata) = getDownloadInfo(pv, options, true)
       let subdir = metadata.getOrDefault("subdir")
       discard downloadPkg(url, pv.ver, meth, subdir, options, downloadDir)
-      developFromDir(downloadDir, options)
+      developFromDir(downloadDir / subdir, options)
 
 proc test(options: Options) =
   ## Executes all tests.

tests/tester.nim

@@ -679,4 +679,9 @@ suite "check command":
 suite "multi":
   test "can install package from git subdir":
     let args = ["install", "-y", "https://github.com/nimble-test/multi?subdir=alpha"]
+    check execNimble(args).exitCode == QuitSuccess
+
+  test "can develop package from git subdir":
+    removeDir("nimble-test/multi")
+    let args = ["develop", "-y", "https://github.com/nimble-test/multi?subdir=beta"]
     check execNimble(args).exitCode == QuitSuccess