Fix detection of dotted ns alias

[nberger]

Due to http://dev.clojure.org/jira/browse/CLJ-1403, a dotted ns alias like [clojure.java.io :as java.io] or [clj-time.coerce :as time.coerce] throws a ClassNotFoundException with the ns alias as the message. Identifying this special case in the regrow process allows us to keep looking for the correct alias

[nberger]

I'll show an example to explain a bit more about this, and why I think it's an important issue:

With the current version of slamhound, I get the following:

› cat src/try_lein_slamhound/core.clj 
(ns try-lein-slamhound.core
  "Testing using dot in alias"
  (:require
    [clojure.string :as string]
    [clojure.java.io :as java.io]))

(java.io/resource "some-resource")

› DEBUG=true lein run -m slam.hound src/try_lein_slamhound/core.clj
... # lein debug output omitted
Failed to reconstruct: #object[java.io.File 0xc69ccdb src/try_lein_slamhound/core.clj]
java.lang.ClassNotFoundException: java.io
        at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
        ....

And the file was untouched.

Without DEBUG=true, the output is worse, just the non-found ns:

› lein run -m slam.hound src/try_lein_slamhound/core.clj            
Failed to reconstruct: #object[java.io.File 0x37811d8d src/try_lein_slamhound/core.clj]
java.io

With this PR applied:

› DEBUG=true lein run -m slam.hound src/try_lein_slamhound/core.clj
# no output from slamhound, only lein debug output

› cat src/try_lein_slamhound/core.clj 
(ns try-lein-slamhound.core
  "Testing using dot in alias"
  (:require [clojure.java.io :as java.io]))

(java.io/resource "some-resource")

Summary: java.io was respected, clojure.string alias was removed because it's not being used, and there was no exception :)

Dotted namespaces are not only respected but are inferred to:

› cat > src/try_lein_slamhound/core.clj 
(ns try-lein-slamhound.core
  "Testing using dot in alias"
  (:require
    [clojure.string :as string]))

(java.io/resource "some-resource")

› DEBUG=true lein run -m slam.hound src/try_lein_slamhound/core.clj
.... # lein debug output omitted

› cat src/try_lein_slamhound/core.clj 
(ns try-lein-slamhound.core
  "Testing using dot in alias"
  (:require [clojure.java.io :as java.io]))

(java.io/resource "some-resource")

@guns: I'd like to know your thoughts about this. I can't say that the implementation is elegant, but it seems to work and is in line with the overally strategy.

To me, this is a blocking issue. I like to be able to use slamhound when I use dotted aliases. One could say "Why are you using java.io when you could use just io". I prefer java.io. And anyways, what about the following:

(:require [clojure.data.zip.xml :as zip.xml]
              [clojure.xml :as xml]
              [clojure.data.zip :as data.zip]
              [clojure.zip :as zip])