TSLint formatter: checkstyle

Formats errors as though they were Checkstyle output.

Imitates the XMLLogger from Checkstyle 4.3. All failures have the ‘warning’ severity. Files without errors are still included.

Sample Output

<?xml version="1.0" encoding="utf-8"?>
<checkstyle version="4.3">
    <file name="myFile.ts">
        <error line="1" column="14" severity="warning" message="Missing semicolon" source="failure.tslint.semicolon" />
    </file>
</checkstyle>