Removed explicit libboost version dependencies

Couldn't compile Smartcoin-QT on my system, had the following error:

/usr/bin/ld: cannot find -lboost_system-mgw46-mt-1_54
/usr/bin/ld: cannot find -lboost_filesystem-mgw46-mt-1_54
/usr/bin/ld: cannot find -lboost_program_options-mgw46-mt-1_54
/usr/bin/ld: cannot find -lboost_thread-mgw46-mt-1_54
collect2: ld returned 1 exit status
make: *** [Smartcoin-qt] Error 1