Allow Text fields to show 0

PHP falsiness strikes again. If a 0 were the value for a Text input, it
would show the default instead.

core/fields/views/fields/field-text.php

@@ -15,7 +15,7 @@
 <input type="text"
        name="<?php echo esc_attr( $name ); ?>"
        id="<?php esc_attr( $args['id'] ); ?>"
-       value="<?php echo $value ? esc_attr( $value ) : esc_attr( $args['default'] ); ?>"
+       value="<?php echo ( $value !== false && $value !== '' ) ? esc_attr( $value ) : esc_attr( $args['default'] ); ?>"
        class="<?php echo isset( $args['input_class'] ) ? esc_attr( $args['input_class'] ) : 'regular-text'; ?>"
 	<?php RBM_FH_Field::input_atts( $args ); ?>
 />