Import django modules only if they are used.

This commit solves the issue #407.
python_ver global python version var added
step should map tables into other data structures issue #58
step should map tables into other data structures issue #58
replacing hardcoded path, caused tests to fail
replacing hardcoded path, caused tests to fail
aims to fix issue #58 for mapping step structures into other data structures but it keeps old datastructures as well in order to maintain backwards compat
Merge branch '58-map-steps-into-other-datastruct'
Fix __repr__ for core classes

__repr__ should return str not unicode
Merge pull request #417 from xavfernandez/fix_repr

Fix __repr__ for core classes
Merge remote-tracking branch 'upstream/master'

Conflicts:
	lettuce/core.py
Add steps and tests for Django mail functionality
Used unused STEP_PREFIX in step regex
Better assert for checking email content
Split out some utils and update tests to use them
Add a couple of extra email steps
New line at end of file
Wrapped directory decorator in a try/finally
Move in_directory decorator to FileSystem class
Add docs