Update transform.py

Added save_to_str method. useful for streaming the final image..
Update transform.py

2 good suggestions from @btel - docstring added and a better method name
Merge pull request #4 from willwade/master

add to_string method
Add Python 3 support
Merge pull request #5 from neurodroid/master

Add Python 3 support
fixed typo where column width and row height was not named correctly
Merge pull request #6 from henjo/templates_bugfix

fixed typo where column width and row height was not named correctly
Added letter-spacing attribute to text objects

`transform.TextElement` now accepts `letterspacing` as an argument
which sets the `letter-spacing` property on the text object.

Also added a test which creates a simple SVG that demonstrates various
letter spacings.
Merge pull request #8 from bradjc/letter-spacing

Added letter-spacing attribute to text objects
Allow style in XML element, to support italic fonts
Merge branch 'master' of https://github.com/btel/svg_utils