Only consider changes when selected and latest are non-blank strings

[robert-stuttaford]

Also:

• Gather changes and print a nice table rather than printing as differences are found
• Print a message if no changes can be found

---

I found that if I used a dep that had no 'latest' version due to there only being SNAPSHOT versions available (viz com.bhauman/figwheel-main {:mvn/version "0.1.0-SNAPSHOT"}), depot would throw a NullPointerException and exit.

I also felt that it would be nice to show the output clearly separated from all the Maven network traffic, so that the eye doesn't have to work to discern changes.

By example, here's what the looks like on /robert-stuttaford/bridge:

|                     Dependency |         Current |     Latest |
|--------------------------------+-----------------+------------|
|              cider/cider-nrepl | 0.17.0-SNAPSHOT |     0.17.0 |
|              clj-time/clj-time |          0.14.3 |     0.14.4 |
|                cljsjs/showdown |         1.4.2-0 |    1.8.6-0 |
|          org.clojure/tools.cli |           0.3.5 |      0.3.7 |
|   org.clojure/tools.deps.alpha |         0.5.417 |    0.5.435 |
| org.eclipse.jetty/jetty-server | 9.3.7.v20160115 | 9.4.10.RC1 |
|              re-frisk/re-frisk |           0.5.3 |      0.5.4 |
|                reagent/reagent |           0.8.0 |      0.8.1 |

[Olical]

:heart_eyes: this is fantastic, thank you so much!

I love the use of pprint and decomplection (adds to browser dictionary) of gather/print. Elegantly fixes the maven output issue too. I was considering capturing everything using with-out-str or something but this is much nicer.

Let's get this published!

[Olical]

(I didn't even know pprint could do this, you learn something every day)