Override Compatibility Mode in Internet Explorer

The X-UA-Compatible meta tag should be added in the head of Apigility
Admin pages to avoid IE rendering the page in Compatibility Mode.
input_filters -> input_filter_specs

Otherwise new API cannot be created
Revert "input_filters -> input_filter_specs"

This reverts commit 81de78a8d240c4b22dded865167f2dc4356e97ae.
Merge pull request #126 from kaloyan-raev/master

Override Compatibility Mode in Internet Explorer
Removed unused test HTML files
Merge branch 'hotfix/126'

Close #126