i18n fix

[louyihua]

1. Add missing '_()' in capa_base.py & video_xfields.py
2. Fix a bug in instructor_dashboard.py that causes crash when ANALYTICS_DASHBOARD_NAME contains non-ascii characters.
3. Workaround for mis-extractions inside .underscore files when using gettext along with interpolate.

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[nedbat]

We should change these two messages to use %(name)s format also.

[louyihua]

@nedbat This is fixed.

[nedbat]

👍

[sarina]

@louyihua Thanks for this fix. Would you mind also updating our i18n guidelines in the docs repo to explicitly call out that we can't have gettext and interpolate on the same line? http://edx.readthedocs.org/projects/edx-developer-guide/en/latest/internationalization/i18n.html#underscore-template-files

Feel free to tag @nedbat in that pull request ;)

[sarina]

Since you're here, can you please change this to use a better variable, eg %(start_date)s?

[sarina]

@louyihua 👍 once you fix that nit about the variable name.

@nedbat can you take care of merging this when that's done?

[sarina]

@dsego gettext doesn't work in the same line as interpolate in underscore templates. Please be sure that you're properly testing your features for i18n. Further, please make sure to give formatting variables proper names when used in translator comments.

[louyihua]

@sarina @nedbat OK, the variable name is fixed.