let git wrappers accept multiple arguments
new subcommand: 'start' a new branch from the SVN head revision or switch to it if it already exists
* added usage for 'start' * fixed order of git commands in 'start' so you always end up in the new branch
added checks for edge cases in 'start': do nothing if already on the new branch, checkout master only if not already on it
moved checks before 'low'-level git commands (are we already on the branch we want to check out/branch/rebase onto?) into wrapper-functions. makes 'high'-level sing functions more understandable.
* added 'info' function to be able to easily disable output * refactored checks before execution of git commands
fix checks before git commands: use actual current branch