[BUG] Plantuml rendering issue, could we swich the PNG to SVG？

[slipb]

1. the Chinese is looking so wired
   
2. the Pictures could not fully be presented
   
3. I guess it's a format issue of PNG, even on the official website, the same thing happened.but SVG looks perfect,
   http://www.plantuml.com/plantuml/uml/SoWkIImgAStDuNe-PSMpZkqAkdOABzOjUR6-yScEjK_tDrifF9-v--dUgSyczpxPEuSBMGgazFcUoK_Nph1I01BFfkpJo4wjj2t9pqxDqyuiq2bBp2bDXN0rmIGNp0uRNHGx5AoWt6ST4vvspN-nVyhJsVCWEd0vwicExcTh5hvOj__bz7LFbsnvsRpYsOHTJtSi0-k2A4LrAz1Ac5kH7VcYR_lJ_caGkvwsRdkoUzgpERrFknQYEn7imwTpLZpPCUNPWeKlL_L0dFgqO-QBxPjVx5tpj6C3nAalrcz_jh7f-QmMPDDGZGO56rWjq1lx5pvhNC_ba9gN0ee20000