Fix typo in package README file

Fix invalid RST back reference caused by missspelt word.
Add .PHONY target to Makefile

The .PHONY target prevents make from getting confused if a conflict
happens to exist between the makefile targets and files in the
repository.
Add base class for command line extensions

All command line extensions are expected to inherit from this base
class.
Rename Bottle and Flask example applications

Both this examples derive from the quickstart examples from their
respective framework's documentation. The suffix on the program name has
been changed to reflect this.
Add command line extension for cgitb module

The begin.tracebacks decorator extends the command line parser with an
argument group for configuring the cgitb module to generate enhanced
reports on uncaught exceptions.