bug 23925 - fix check for NumEvent > 0 in BaxH5Reader._sequencingZmws	

[git-p4: depot-paths = "//depot/software/bioinformatics/lib/python/pbcore/": change = 127040]
Bump pbcore version to 0.7.0 for 2.1 release

[Tracking bug 23893]

[git-p4: depot-paths = "//depot/software/bioinformatics/lib/python/pbcore/": change = 127216]