(Repeats, without changes, story from March 22 about jihadists and Tunisia) By Patrick Markey TUNIS, March 22 (Reuters) - Praised as a model of Arab Spring progress, Tunisia has finally been drawn onto the global jihadi battlefield after Islamist militants gunned down foreign tourists in a brazen assault at the heart of the capital. The storming of the Bardo museum inside the heavily guarded parliament compound was more deadly evidence Islamist militants are turning to **rth Africa as a new front beyond their main battlegrounds in Iraq and Syria. Libyan and Tunisian jihadists have streamed to the ranks of Islamic State and other militant groups in Syria and Iraq.