converted documentation for "Using fixtures"
converted documentation for "Debugging failing tests"
converted documentation for "Using different testing libraries"
converted documentation for "Test execution environments"
created folder for Reference documentation
converted documentation for "Command line flags"
converted documentation for "Config files"
Updating #introduction and #reference sections

Still todo:
 - #reference - config section
Adding reference files
Merge pull request #2 from rbakr/master

Updates to reference and getting started portions of the docs.
Merge branch 'docs_tutorials' of https://github.com/roelrz/docs into roelrz-docs_tutorials

* 'docs_tutorials' of https://github.com/roelrz/docs:
  converted documentation for "Config files"
  converted documentation for "Command line flags"
  created folder for Reference documentation
  converted documentation for "Test execution environments"
  converted documentation for "Using different testing libraries"
  converted documentation for "Debugging failing tests"
  converted documentation for "Using fixtures"

Conflicts:
	source/reference/annotations.rst
	source/reference/command_line_flags.rst
	source/reference/config_files.rst
fixed merge issues