Merge pull request
#1363 from minrk/qtstyle
Fix some minor color/style config issues in the qtconsole
The tabbed code changed a few things about loading styles and stylesheets in the qtconsole, which this resolves, among a couple other small color-related issues:
* tabs other than the first get colors
* IPythonWidget.style_sheet configurable is not clobbered by defaults
* style_sheet configurable would cause a crash, because _style_sheet_changed could be called before _control existed
* fix str->unicode token preventing stylesheets without syntax highlighting from working
* fix typo in the function used to detect whether a bgcolor is dark or light
