The test_case_template.hpp header is deprecated in Boost, and the
latest Boost version is now throwing warnings during the build.
In Boost 1.59 (at least), this header is included transitively by the main
Boost test header, so this header is not needed by any supported Boost
version.
* Fix wildcard display in the file selector dialog (on GTK
it would show the regex to the user)
* Move the file extension comparison into a common function
The returns of KiCad file extensions on GTK contain basic regex matching
case-insensitive file extensions. We need to match these in the
provider and tests