Ecospace results grid incorrect for the "End:" period

[joeb]

Under some circumstances the last time step will not contain data. So the end result will be wrong, it is missing data in the last time step. To work around this do not include the last year in the summary period, set the "End:" value to two years less than the Total run time. This does not include the last time step and the data summary will be correct.
This is being caused by rounding error in the main Ecospace time loop. In some circumstances it will not include the last time step.

[jeroens]

Could be related to #1126, first fix that one

[joeb]

Ecospace would sometimes exit the main time loop before the last time iteration due to small rounding error. I made sure it loops to the last time step.