BlockExtract arguments are not easy to understand

[computerality]

Maybe have --blocks-out be -o?

$ ./BlockExtract -f ../../tests/ELF/ls_x86
[ Error ] You must have an output file specified
options:
-h [ --help ] print help
-f [ --file ] arg input file
-a [ --arch ] arg architecture - x86, x64, arm, thumb
--raw interpret input file as raw blob
--block-size arg max size in statements of blocks to search
--blocks-out arg seralize input to a DB