WIP implement simplest version of paras.  links don't work yet.
un-implement already implemented para function.
simplify new replace implementation.
an awful thing that makes good-reminder mostly work.

also, a much more functional version of TextBlock#replace, but a much uglier one.  submitted only for feedback and refactoring.
cleaned up work on making replace respect styling info.
Merge remote branch 'remotes/tehgeekmeister/implement_paras'
Refactor tehgeekmeister's work and fix #183.