Clean matrix arguments
Originally the parse tree was a binary tree, from that
time matrix element were put into that data structure.
This was partially undone, but not full which leads to some artifacts
in matrix cells.
One of the problem is that due to the binary parse
tree structure the postprocessing did not correctly
identfy \limits.
This change changes reduces nesting from matrix, and regards
matrix instances as two-dimensional TexArrays.
Bug: T362344
Change-Id: I66a31a09f204709a51d6b5c9ecefc083f7ee2d6d
13 files changed