build-glyphs binary - allow different buffer sizes

[saskaale]

Passing optional parameter bufferSize to the build-glyphs binary. It allows user to create bigger ( or smaller ) font chunks.

[springmeyer]

Thanks for the contribution. This will need test coverage in https://github.com/mapbox/node-fontnik/blob/master/test/bin.test.js#L17-L33. I'm curious, what is your usecase for creating different sized font chunks?

[saskaale]

Hi. Thanks. I have also prepared second pull request with the argument checking ( buffer size > 0 ). I'd send it in evening.

Ok, I'd write that test coverage.

And for the usage: I am developing library which uses the SDF fonts and I don't want to cope with the loading of all (or just necessary ) files. I'd simply tell the user to generate the range he'd need ( assuming that almost everyone would use just ASCII range, but if he'd want more, he can just simply generate for example whole UTF8 range ). With that, I can simplify the library and work with just one file load.

[saskaale]

Hi Dane,
I 've already wrote that coverage. Hope, it would be OK.

[mikemorris]

Could we use a more accurate term like rangeSize or something? buffer is already an argument to RenderSDF (currently hardcoded to 3) indicating the spacing around each rendered SDF.

If you're writing a library, could you just call RangeAsync (C++) or Range (JavaScript) directly instead of going through the CLI interface?

[saskaale]

I have no problem with the renaming of the argument. RangeSize seems good to me.
I wanted to build web-based library which uses directly just the directly pbf files, so this seemed to me as an easiest solution.