TTF output and style preservation

So, I tried using the Ubuntu Mono OTF fonts from Lokaltog/powerline-fonts but the look terrible.  I think hinting and kerning information is lost in the conversion.  So, I've modified the font patcher to output either OTF or TTF based on the input format.  As a bonus, it's also faster.

The second commit here fixes styles, which get broken by appending `ForPowerline` to fonts with style suffixes in the fontname, ie - `UbuntuMono-Bold`.  Instead of simply appending `ForPowerline`, which results in a style of `BoldForPowerline`, it inserts it before any style information, ie - `UbuntuMonoForPowerline-Bold`, which preserves the correct style of `Bold`.