Rewrite #2
Some work on pairs
Added a nice Make_SCMT utility function
Fixed representation of strings to be correct
Added note about handlign correct bahaviour later
Pair printing now seems to work correctly in all ways - added test to match
Lists now print properly, test added

Turns out my reflection logis was incorrect
Added scheme nil type
re-aded note on efficiency
Improved the quality of the tests
Changed scm_print to simply String() which should allow these to just be printed
Added test for SCM_Nil type