Restore Verilator model support.
Created by: jeremybennett
Commit 74abb26 removed support for creation of a Verilator
library, used for the debug simulation target and standalone
simulator. This commit restores the target and documents it
better in README.md, so people know it is there!
Files changed:
* .gitignore: Ignore model-lib.log.
* Makefile: Add model-lib as a phony target to invoke fusesoc.
* README.md: Document the model-lib target.
* core-v-mcu.core: Add model-lib as a target with associated
filesets and script declarations.
Signed-off-by: Jeremy Bennett jeremy.bennett@embecosm.com