* Touch up readme info graphics

* Add layers to easily recreate the single steps
* Re-group objects
* Transform white rectangles for interrupting arrows into paths
* Adapt rectangle path forms to make arrow interruptions nicer
* Centre repository names in their repository boxes
* Add simple to hack to remove double rounded border problem in step 3
* Set background colour to white (was transparent before)
* Update repo cloning graphics to reflect changes in SVG file; optipng'ed
* Fix newline problems in repo cloning graphics SVG

* Remove superfluous newlines
* Add missing newline at end of file
Merge pull request #388 from stevenkoenig/fix-readme-info-gfx

Fix readme info gfx
Add link to older installers for Git for OS X

The current Git installer for OS X is broken for many pre-10.8
systems. The older installers seem to solve this problem.