Removed some unused imports from unit tests.

tests/test_possibilities.py

 import unittest
 
 from src.possibilities import MESSAGES, Possibility as P
-from src.rules.numerics import add_numerics
 from tests.rulestestcase import tree
 
 from src.parser import Parser

tests/test_rules_absolute.py

 from src.rules.absolute import match_factor_out_abs_term, \
         remove_absolute_negation, factor_out_abs_sqrt, absolute_numeric, \
         factor_out_abs_term, factor_out_abs_exponent
-from src.node import ExpressionLeaf as L, Scope
+from src.node import Scope
 from src.possibilities import Possibility as P
 from tests.rulestestcase import RulesTestCase, tree
 

tests/test_rules_lineq.py

 from src.rules.lineq import match_move_term, swap_sides, subtract_term, \
         divide_term, multiply_term, split_absolute_equation
-from src.node import Scope
 from src.possibilities import Possibility as P
 from tests.rulestestcase import RulesTestCase, tree
 

tests/test_rules_sqrt.py

 from src.rules.sqrt import is_eliminateable_sqrt, match_reduce_sqrt, \
         quadrant_sqrt, constant_sqrt, split_dividers, \
         extract_sqrt_multiplicant, extract_sqrt_mult_priority
-from src.node import Scope, sqrt
+from src.node import Scope
 from src.possibilities import Possibility as P
 from tests.rulestestcase import RulesTestCase, tree
 

tests/test_strategy.py

-from src.rules.factors import match_expand, expand_double, expand_single
+from src.rules.factors import expand_double, expand_single
 from src.node import Scope
 from src.possibilities import Possibility as P
 from src.strategy import find_possibilities