Fixing problems with #16's use of launch_presentation_locale

Updating code to look at UserProfile.language_proficiencies; updating tests; iterating version to 1.0.8

Transmit launch_presentation_locale parameter

Added display name and due date to LTI Parameters

Forgot to compile Sass for previous style update of the LTI launch button

Increment setup.py version for release 1.0.6

Visual styling for LTI external button

adjust LTI external button to be aligned to the left and have spacing between text and its rendering

PHX-256 Added a white background to the modal window close button

asadiqbal08/WL-356: Add I18N support

asadiqbal08: Updated branch as per suggestions
asadiqbal08: Addressed PR feedback
mattdrayer: Rebased branch, addressed merge conflict

Updated setup.py version

fix bug where custom_parameters field is empty

PHX-255 Launch LTI provider on modal window open

PHX-241 Make modal display responsive

TNL-4046 Fix due date comparison bug

Use django.utils.timezone.now() when determining if the due date of a component has passed to avoid tz-aware/naive datetime comparison bug

PHX-207 Accessibility Improvements

Toggle aria-hidden attribute on modal window open/close; Set title attribute on iframe to display name of component; Remove aria-labelledby attribute from modal body; Make modal overlay id attribute unique'

Do not pin dependency versions

Sprint Solutions:Zug PHX-200 PHX-201 XBlock LTI Consumer