Kinetis flash algo fixes plus some misc changes

Fixed incorrect flash margin used for verify program flash command in Kinetis flash algos. This was causing USB MSD flash programming to fail.

Also includes some additional changes:
- Fixed LPC11U35 bootloader project build.
- New flash_algo_gen_all.py script that processes all .axf files in the tmp dir.
- Fixed unused variable warning in Kinetis check_security() function.
- Updated build.py with missing or incorrect targets.