Added stretchy attribute to XMTok
exposed stretchy as option to DefMath
Added stretchy attribute to XMTok
recognize sequences of prescripts more carefully, and very carefully arrange them to preserve when they do and don't stack
adapt script combining; make bigops actually be big; mark the oldstyle math accents as NOT stretchy
rework \sideset so that it preserves offset (floating) scripts
use new stretchy attribute
use new stretchy attribute
tweaking font to mathvariant mapping; added some classes to help cover odd cases; propogate/infer stretchy, symmetric
enhanced math accent testcase
updated testcases for new stretchy attribute
tentatively added ltx_font_mathcaligraphic class
updated sideset test for more variations