Chris kira semantic analysis

Merging to master -- print functions are in LRX style (with brackets) and bug fixed in assign/accessing children.

Still need to accomplish the following.
WRITE::
1) Addition of trees
2) Pop of trees
3) Comparison of trees
THOROUGHLY TEST::
1) Tree child accessors t%0%2
2) Tree child assignment t%1 = t2

@mychrisdangelo @dmb2168