Meaningful variable names

[Lin777]

Fixes #16

Now generate test like:

test30
  "Fitness: 
block-coverage: 4.762
"
  "This test covers: 
block-coverage
SFoo:4.762%
"
  | _aSFoo0 _anOrderedCollection1 _aDictionary2 |
  _aSFoo0 := SFoo new.
  _anOrderedCollection1 := _aSFoo0 returnCollection.
  _aDictionary2 := _aSFoo0 return: _anOrderedCollection1.
  self assert: _anOrderedCollection1 equals: _aDictionary2.
  self assert: _aSFoo0 score equals: 0.
  self assert: _anOrderedCollection1 printString equals: 'an OrderedCollection()'.
  self assert: _aDictionary2 printString equals: 'an OrderedCollection()'