add r11780 pmt, load surfaces from db, various fixes

* Modify "sphere" geometry to match "challenge" requirements
* Add model for Hamamatsu R11780 HQE PMT
* Load optical surfaces dynamically from DB rather than hard-coding in
  Materials.cc
* Fix a failure to sample the PMT charge and write the front-end time,
  which was an oversight while sanitizing RAT for public use.
fix implicit double to int cast (caused warnings)
Merge pull request #4 from mastbaum/r11780

add r11780 pmt, load surfaces from db, various fixes