Readme update#17

Merged

isiyu merged 4 commits intodevelopfrom

Apr 18, 2017

Commits on Apr 18, 2017

Updating readme with links to documentation site. This removes redundancy of information.
David Rhodes
committed
Added API link.
David Rhodes
committed
Added another known issue (regarding building roofs and terrain)
David Rhodes
committed
include version in README
isiyu
committed