README.md: use same installation guide for hydro and indigo (resolves #336)
README.md: use same installation guide for hydro and indigo (resolves #336)

As the installation guide for hydro and indigo only differs in
small details, the same wiki page is used for the hydro and indigo
distribution.

Signed-off-by: Lukas Bulwahn <129af72297ae3dc7f8b596ccbac8c9d4dd733ed6@oss.bmw-carit.de>

rapyuta/meta-ros,bmwcarit/meta-ros,simium/meta-ros,simium/meta-ros,bulwahn/meta-ros,bmwcarit/meta-ros,bulwahn/meta-ros,rapyuta/meta-ros,rapyuta/meta-ros,simium/meta-ros,bmwcarit/meta-ros,bulwahn/meta-ros,bmwcarit/meta-ros