CiviCase label and title simplification to increase adaptability

CiviCase is increasingly used for workflows that are not 'classically' case management. In order to make the UI more adaptable for these use cases we should eliminate un-needed use of the 'Case' prefix on component Dashboard (summary section and selector column headers), Cases tab and Manage Case screen.

Manage Case Screen
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"Case Summary" => "Summary"
"Print Case Report" => "Print Report"
"Case Roles" => "Roles"
"Case Activities" => "Activities"
"Assign to Another Client" => " .. to Another Contact"

Dashboard / Selector
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"Summary of Case Involvement" => "Summary of Involvement"
"Client" => "Contact"
"Case Type" => "Type"
"Case Manager" => "Manager"

NOTE: This supplements the CiviHR specific word replacement for Case => Assignment (http://issues.civicrm.org/jira/browse/HR-199) which will handle instances of the term Case that are not referenced in the list above.