RelEx2Logic test cases

RelEx2Logic test cases.

This depends on https://github.com/opencog/relex/issues/98 / incorporates pull request https://github.com/opencog/relex/pull/106

To run tests using Maven:

    mvn test
    
To run tests using Ant:

    ant test-logic
    
or:

    ant test

Currently there are 3 test cases, all success:

![selection_411](https://cloud.githubusercontent.com/assets/24123/3537378/e3214928-081e-11e4-8d31-71fb285cd9d3.png)

We probably want more test cases to expand RelEx2Logic's knowledge :)

Sample Output:

```
Info: sentence: "Trees are plants"
Link-parsing: 1 milliseconds (avg=1 millisecs, cnt=3)
RelEx processing: 18 milliseconds (avg=21 millisecs, cnt=3)
10:51:54.575 [main] INFO  relex.output.LogicViewTest - ; #1: (S (NP Trees.n) (VP are.v (NP plants.n)))

10:51:54.575 [main] DEBUG relex.output.LogicViewTest - Binary relations: [_obj(be, plant), _subj(be, tree)]
10:51:54.575 [main] DEBUG relex.output.LogicViewTest - Unary relations: [subscript-TAG(be, .v), pos(be, verb), tense(be, present), subscript-TAG(plant, .n), noun_number(plant, plural), pos(plant, noun), subscript-TAG(tree, .n), noun_number(tree, plural), pos(tree, noun)]
(ListLink (stv 1 1)
   (AnchorNode "# New Parsed Sentence")
   (SentenceNode "sentence@b67dd1be-3b4d-4daa-a428-952aef68e560")
)

10:51:54.582 [main] INFO  relex.output.LogicViewTest - Logic relations: [(be-inheritance-rule "tree" (get-instance-name "tree" "trees@cc071adb-25f5-4fbd-8093-d7a7082fe24f" (ParseNode "sentence@b67dd1be-3b4d-4daa-a428-952aef68e560_parse_0")) "plant" (get-instance-name "plant" "plants@ce76b112-8b42-4d1b-80c6-ae5abc280f5d" (ParseNode "sentence@b67dd1be-3b4d-4daa-a428-952aef68e560_parse_0"))), (tense-rule "be" (get-instance-name "be" "are@06200eae-288c-47e6-9ef4-a32fe064e8d3" (ParseNode "sentence@b67dd1be-3b4d-4daa-a428-952aef68e560_parse_0")) "present")]
Tests run: 3, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.75 sec
```