Switch to click for command line processing
Use click's built-in version_option option
Use click's Path type for file handling
[QA] Update api/commandline doc
Switch to click's colourised output
[Tr] Update to click 2.0's new BadParamater errors
Merge branch 'f/click'

Closes #9.

* f/click:
  [Tr] Update to click 2.0's new BadParamater errors
  Switch to click's colourised output
  [QA] Update api/commandline doc
  Use click's Path type for file handling
  Use click's built-in version_option option
  Switch to click for command line processing

Conflicts:
	versionah/__init__.py