nextpnr 0.10

• archapi: New "resources" API to represent mutually exclusive routing resources
• gatemate: Performance improvements, floorplanning support, support for use of more routing resources
• gowin: initial GW5AST-138C support, GW5 DSP support, router2 support for faster routing, significant placement and routing performance improvements
• nexus: IO DELAY support and misc improvements
• xilinx: initial Kintex-7 support, improved MMCM/IO support and reliability