Basic installation guide in README.md
Basic installation guide in README.md

Signed-off-by: Ealden Esto E. Escanan <ff27627daef6b3172da4425363457b1137a9e29e@gmail.com>

ealden/gradle-androidannotations-plugin,peterdocter/gradle-androidannotations-plugin,ealden/gradle-androidannotations-plugin