Improve formatting, English, and consistency

[IsaccBarker]

Fix #114.

Also, I was unsure whether to use xmake, Xmake, XMake, or xMake. All four are used in various places. I went with the second option, and corrected as I went, because that's the style of the first Xmake that occurred in the REAMDE.

[waruqi]

Great work, thank you very much. 👍