Improved error reporting and print syntax.

R=neil.fraser@gmail.com

Review URL: https://codereview.appspot.com/9759043

git-svn-id: http://blockly.googlecode.com/svn/trunk@1014 c400ca83-b69d-9dd7-9705-49c6b8615e23
Add repeat block that use number block instead of inline input field.  Factor out number detection in generators.  Fix fractional slices in Python.
Review URL: https://codereview.appspot.com/9784043

git-svn-id: http://blockly.googlecode.com/svn/trunk@1015 c400ca83-b69d-9dd7-9705-49c6b8615e23