fix carry slot values for checks
fix state name check for increment-tens production
switch to storing all numbers as strings
added productions for speaking result
put 0 in for second tens if there is none so the answer comes out the same
fill non-existent tens place of first addend with 0
fixed goal state name
added option to specify problem in run function
only speak ones place if tens is 0
added specific slots for first and second tens places to goal chunk type
don't do imaginal if no second tens
added production to copy second tens value to goal after encoding
don't do imaginal encoding if no tens place in first addend
don't match imaginal or add second-tens when encoding first tens
added production to store first tens value to goal after encoding
added production to do 'add' when there are no tens
added production to do add when there is only tens in first addend
added test that first tens is not nil
added production to add when only second addend has tens place
updated method for adding values when both addends have tens places