Fix tabular renderer ext matching error
Fix tabular renderer ext matching error

If a file with an extension that had casing that was not all lowercase
was passed to the tabular renderer, it would not match it with the
proper function.

AddisonSchiller/modular-file-renderer,TomBaxter/modular-file-renderer,felliott/modular-file-renderer,TomBaxter/modular-file-renderer,TomBaxter/modular-file-renderer,AddisonSchiller/modular-file-renderer,CenterForOpenScience/modular-file-renderer,AddisonSchiller/modular-file-renderer,TomBaxter/modular-file-renderer,AddisonSchiller/modular-file-renderer,CenterForOpenScience/modular-file-renderer,CenterForOpenScience/modular-file-renderer,CenterForOpenScience/modular-file-renderer,felliott/modular-file-renderer,felliott/modular-file-renderer,felliott/modular-file-renderer