Censor colons for ConfigParser
Censor colons for ConfigParser

Because ConfigParser is hard-coded to parse colons as assignment
operators, lines such as:
!asdfasdfasdfasdf:matrix.server = 0.01
turns into:
!asdfasdfasdfasdf = matrix.server = 0.01
To prevent this, we replace colons as '-colon-' when we save the
response rate settings.

Spferical/matrix-chatbot,Spferical/matrix-chatbot,Spferical/matrix-megahal