Default preferences.plist assume "Hei" font available about sunpinyin

[tchaikov]

thanks @yegle.

i also uploaded a pre-built bundle at https://sourceforge.net/projects/open-gram/files/sunpinyin/? which has the latest open-gram lexicon and language-model included, in case you are interested.

[difanz]

I debugged with @yegle this afternoon. Since Hei is not available as a default font in Yosemite, I suggest to update default preferences as well, not to mention Hei is an ugly font.

I propose to use Helvetica (and System will choose Chinese fallback font) or STHeiti as the default font.

[tchaikov]

thanks, tifan. i have no strong opinion w.r.t. what the default font we should have in sunpinyin. but i would say that STHeiti might be a better choice if Hei is not a pleasant one in your opinion. as our focus now is to offer our user a better experience of inputting Chinese, having a Chinese font as the default setting would be more appropriate in this case, despite that Helvetica is obviously ubiquitous, and the system will always provide a fallback in case it fails to cover the code point in question. hope it makes sense.

i will update the plist if no objections. as always, PR is also welcome.