turn peripherals into scoped singletons

.gitignore

src/exception.rs

src/itm.rs

src/peripheral/cbp.rs

src/peripheral/cpuid.rs

src/peripheral/dcb.rs

src/peripheral/dwt.rs

src/peripheral/fpb.rs

src/peripheral/fpu.rs

src/peripheral/itm.rs

src/peripheral/mod.rs

src/peripheral/mpu.rs

src/peripheral/nvic.rs

src/peripheral/scb.rs

src/peripheral/syst.rs

src/peripheral/tpiu.rs