Fixed speaker category to check for null image types
Merge branch 'master' of https://github.com/TEDxCT/tedx_ios

# By Daniel Galasko
# Via Daniel Galasko
* 'master' of https://github.com/TEDxCT/tedx_ios:
  event info won’t open google maps now
  hide tab bar when pushing for talks, looks cleaner,
  cleanup