changed variable name 'data_i' to 'frame_i' in some places
General code clean up. Fixed bug when filling 20Hz epoch values.
Fixed bug with some default values being set to -1 instead of appropriate fill values
Fixed a number of bugs having to do with how data are stored in the DataHolder object.
Fixed LevelTwo MSPC data DataHolder.size() call.
Fixed L2 SSPC where it was only copying 48 samples to the CDF
Merge branch 'master' into fix_epoch

Changed documentation file name.
Removed old data from CDF Skeleton Files.
Fixed issue with record numbers for <1Hz not being calculated correctly. This caused problems with spectral data gaps and time stamps.
Simplified code for converting between different time standards. Set the mod4,32,40 epoch values to the start of their accumulation period.