moving HISTORY.txt to markdown format
fixing headings
A (potential failure of an) attempt to use alternate headings to make things easier to read as flat text, and also to use relative anchor links, and also to convert 'MLPACK' to 'mlpack' for consistency.
Conjugatin' da verbs.
Add download link, for people who come across mlpack via Github but might be better served by a stable version.
I meant for this to be bold, and vim even told me it wasn't going to be, but typical me, I did not listen.
Merge pull request #5 from ajkl/master

moving HISTORY.txt to markdown