add the OS name to every headline

Change-Id: I98b3524b0d4ce3c73fabca023163364296b2ce32
fix backquotes

Change-Id: I7c6fb08c2cdfb53acbfa5bdd2783f431e2e09bf3
improve readability of links

Change-Id: Ifa217b88dec5fba9b4db81969e4a4ee17c4c1075
fix more backquotes

Change-Id: Ied1827f6a1824baf70dec343e7eeee352c0df4bc
some spelling and OS X headline

Change-Id: Iabd0db9de7f76349c67c7adc7fd243ad2428df01