Fixes responseWriter.Size()
Fixes responseWriter.Size()

- "written" boolean is not longer needed
- size is reseted
- addition instead of assignation

henrylee2cn/gin,marcelaraujo/gin,gaowenbin/gin,helight/helight_code,VishvajitP/gin,abduld/gin,jjz/gin,michelangelo13/gin,bfosberry/gin,hayd/gin,helight/helight_code,snyh/gin,sanathb/gin,helight/helight_code,agaurav/gin,tvmaly/gin,AnuchitPrasertsang/gin,bfosberry/gin,go-go/gin,RomanMinkin/gin,abduld/gin,weisd/gin,marcelaraujo/gin,dayed/gin,cention-mujibur-rahman/gin,sanathb/gin,jacobxk/gin,hayd/gin,jimmykuo/gin,0prototype/gin,gin-gonic/gin,helight/helight_code,thinkerou/gin,AnuchitPrasertsang/gin,agaurav/gin,adwinsky/gin,sdvdxl/gin,sosedoff/gin,sanathb/gin,michelangelo13/gin,JustinBeckwith/gin,adwinsky/gin,helight/helight_code,cention-mujibur-rahman/gin,michelangelo13/gin,helight/helight_code,hayd/gin,helight/helight_code,gamescores/gin,jacobxk/gin,aiyi/gin,adwinsky/gin,jacobxk/gin,disintegrator/gin,jithinjk/gin,helight/helight_code,cention-mujibur-rahman/gin,b54898533/gin,weisd/gin,weisd/gin,CodyGuo/gin,calavera/gin,JustinBeckwith/gin,marcelaraujo/gin,helight/helight_code,cch123/gin,agaurav/gin,abduld/gin,JustinBeckwith/gin,jithinjk/gin,nubunto/gin