Replace All, Replace work w/ a few minor bugs

Work in reactions table. Both work with or without match case. Replace
will replace all instances one at a time.
Bugs: Need listener for match case. Reversible column if it would
bechanged to invalid value by replace all, just retains old value, no
error. Also reaction equation if contains multiple instances of find
string is unhighlighted and then rehighlighted next find click. other
columns do not do this.