Convert text markup from IRC to Telegram

[eelcohn]

0x02 bold text 0x02 --> bold text
0x1D italic text 0x1D --> italic text
0x1F underlined text 0x1F --> u̲n̲d̲e̲r̲l̲i̲n̲e̲d̲ ̲t̲e̲x̲t̲
0x0F --> if is open, then ; if is open, then