Moved env variable setting to after optparse

so environment can be set depending on backend choice
Added sysclk period const to kc705 xdc
Charged message format of spi->wb bridge

To match that of the current spifpga code
Added bin generation to vivado, other tweaks

Added tcl command so vivado generates bin file
Fixed logger -> self.logger bug in an error clause
moved polatform source file addition to build_top method
Added core_info.tab for kc705