Create initial version of the PyGit libarary

[dl1998]

Create basic functionality

• General
  • Read Git configuration
  • Update Git configuration
  • Execute raw Git command
• Repository
  • Init repository
  • Clone repository
  • Use existing repository
• Change management
  • Add files/folders
  • Remove files/folders
  • Move files/folders
  • Create commit
  • Create tag
  • Create a new branch
  • Switch between branches
  • Pull changes
  • Push changes