Use VeraCrypt option by default; add --disable-veracrypt option.
While TrueCrypt is no longer developed and supported since 2014, VeraCrypt devices (as a successor of TrueCrypt) are much more used today.
This patch switch default to scan for VeraCrypt signature, making --veracrypt option obsolete (ignored by default as it is default).
If you need to disable VeraCrypt support, use new option --disable-veracrypt.