Text formatting usability improvements

[chilimangoes]

• Remove implicit "set format" (see Remove implicit "set format" from text formatting commands #158). The "set format" command also now prints the new text format to the NatLink window (see "peek format" command below)
• Added "clear caster formatting" command. I find that sometimes it's convenient to be able to output text without any added formatting into a program that's not supported by Dragon (eg comments in code files).
• Added "peek format" command, which will print the current text format to the NatLink window. For example, it will print something like Text formatting: laws spine (this-is-a-test).