Add p95 into the latency statistics

[Sudiksha]

General trend is to capture p90, p95 and p99.
Added changes to produce output for p95 response time latency stats too. Please review and merge.

[DiegoBetancourtC]

While this push request is accepted, you can use this:

FROM alpine:latest as build
RUN apk add --update alpine-sdk perl linux-headers
RUN cd /tmp                                 && \
    git clone -b 4.2.0 https://github.com/wg/wrk
RUN cd /tmp/wrk                             && \
    sed -i 's/90.0, 99.0/90.0, 95.0, 99.0/g' src/wrk.c && \
    make 

FROM alpine:latest
COPY --from=build /tmp/wrk/wrk /usr/local/bin/
RUN apk add --no-cache libgcc
WORKDIR /data
ENTRYPOINT ["wrk"]