Update mplotqueries.md
Update mplotqueries.md

added x-axis picking, and concluding part I of tutorial.
devkev/mtools,rueckstiess/mtools,corymintz/mtools,parkhyeonghwa/mtools,tomzhang/mtools,corymintz/mtools,parkhyeonghwa/mtools,yaowenqiang/mtools,gormanb/mtools,tomzhang/mtools,ces0712/mtools,gormanb/mtools,parkhyeonghwa/mtools,aerrami/mtools,yaowenqiang/mtools,gormanb/mtools,aerrami/mtools,devkev/mtools,aerrami/mtools,yaowenqiang/mtools,tomzhang/mtools,rueckstiess/mtools,corymintz/mtools,ces0712/mtools,devkev/mtools,ces0712/mtools