Updating GitExtensions instructions for MAC

Simplest step by step on how to configure GitExtensions over a MAC
Merge pull request #14 from fraga/patch-1

Updating GitExtensions instructions for MAC
add different html output scripts
add section about Orphan branches
Merge pull request #15 from feinstaub/topic_build

add section about Orphan branches
Merge pull request #16 from gitextensions/master

Update