Edited code to remove dependence on *.nml file to get date/time
Also changed code to use R POSIXct class instead of Date to support sub-daily addressing
Cleaned up code for readability and added/changed verification for functions which only work with one year of data
Fixed the "one-year" check code.

I had forgotten to take the difference of the date range to get a difftime object
Restored fishExamples.r, a erroneous delete
Fixed "fishExamples.r" to be consistent with improved GlmPhysicalDerivatives.r functions.
Merge pull request #2 from lawinslow/master

Improvements to GLM code