fix #125 on master, now $ splits TextBlock

like it should, rather than jumping to the end of TextBlock

cherry-pick of e39ade08ff7b57daed06ac2093098f676ed94914

Conflicts:
	src/commands.js
fix #122 on master, now Spacebar works in TextBlock

specifically, now {Shift-,}Spacebar types a space in {Root,}TextBlock

cherry-pick of 167b9115f2afffe800e12ed1c3eabdec8ed5d6ec
stop LiveFraction at commas/colons/semicolons

manual cherry-pick of #157 onto master
make the livefraction change in master mirror the one in dev (since that one actually works)
Merge pull request #177 from mathquill/live-fraction--sdspikes

make the livefraction change in master mirror the one in dev (since that one actually works)
v0.9.2
don't use tar --xform - it's not in bsd
feature-detect for sed flags across gnu/bsd

specifically, `sed -r` vs. `sed -E` for extended regexps, and different
argument patterns for `sed -i`.
sort --version-sort is not supported in bsd.

We used custom keys and the . delimiter to achieve the same effect.
Merge branch 'build.cross-platform'
hotfix for #164: don't parse 'oRZQ' like '\o\R\Z\Q'

see #164 for explanation