Update Readme.md

Add grunt-contrib-imagemin in Grunt Plugins.
add Orthogonal
Update contributing file
Added Python Library of SVG
Merge pull request #24 from davidchambers/orthogonal

add Orthogonal to tools
Added Python Library of SVG
Merge branch 'master' of github.com:guilouro/awesome-svg
Merge pull request #27 from guilouro/master

Added Python Library of SVG
Merge pull request #25 from LFeh/master

Add grunt-contrib-imagemin in Grunt Plugins.
Add Concepts: Smarter Sketching
Merge pull request #28 from tophatch/master

Add Concepts: Smarter Sketching
Add grunt-svgstore link
Merge pull request #1 from willianjusten/master

merge in new changes from origin