Parse scores of positive or negative infinity
Support +inf and -inf where doubles are returned

* Replaces all uses of Double.valueOf with a method that supports positive
and negative infinity.
* Adds positive and negative infinity to the tests
Merge commit 'pull/upstream/463'

Conflicts:
	src/main/java/redis/clients/jedis/BuilderFactory.java
	src/test/java/redis/clients/jedis/tests/commands/SortedSetCommandsTest.java