swd_read_block() / swd_write_block() misalignment

Hello,

the two functions swd_read_block() and swd_write_block() will stumble into misalignment, if their callers swd_read_memory() and swd_write_memory() are called with differently aligned src/dst, e.g. "address"=0x20001ef**1** (target), "data"=0x20013ee**0**.

Important part are the last digits. If the addresses have a different alignment, swd_read_block()... crashes, because the function actually expects "data" to be 32bit aligned.

Fix is easy: first read the 32bit value from the target into an aligned value and then do a memcpy() from this value to the actual destination.

If performance is an issue, the special case "misaligned" has to be handled extra.

If I should provide a PR, let me know.

Start by tracing swd_read_memory() and swd_write_memory() into swd_read_block() and swd_write_block(), then inspect how destination and source alignment are handled. Reproduce the differently aligned address case described in the issue and verify that block reads and writes complete without misalignment crashes.

Written by the indexing model from the issue text.