Things that don't pass yet in the testsuite:
* %previous
* objects (<call> etc)
* topics: inherits and includes

Things still to implement:
* substitutions, person substitutions
* sentence-casing, <sentence>
* inline redirects, {@}
* ignore inline commands when parsing
* global variables
* handle the BEGIN block
* saving recent chat history, and <input> and <reply>
* check if the programmer forgot to call sortReplies()
* <bot> vars, <get> vars, <input>, <reply> in the trigger regexps
* converting literal "\n" into line break in processTags isn't working
* the {random} tag
* <env> tag for global vars
* {!stream} tag
* {person} substitutions (see bullet 1)