Consistent default for strict argument

[jennybc]

In the reboot I use the strict argument in several functions that parse or generate string representations of cell references. It only affects A1 formatted references.

When strict = FALSE, A1 is interpreted as the cell in the first row and first column. I.e. it is interpreted as an absolute reference, though strictly speaking you should really have said $A$1. Likewise, strict = FALSE means that the A1 formatted string generated for the upper left cell would be A1 instead of $A$1.

Right now I have inconsistent defaults for strict. For user-facing stuff (re: cell_limits objects), it's FALSE, whereas functions more likely to be used in programming or another package (re: ra_ref and cell_addr objects) have a default of TRUE. Is this just confusing?