Use a XML pull parser instead of pattern-matching for gcvote

Benchmark results on Nexus 5:
- XML GCVote parsing (current) in ms (1000 times): 2678
- Regex GCVote parsing (old) in ms (1000 times): 3986

Benchmark results on Nexus 7 (2013):
- XML GCVote parsing (current) in ms (1000 times): 3448
- Regex GCVote parsing (old) in ms (1000 times): 6075