Add argument to specify path to ROMs

[nvllsvm]

Adds a new argument -d: to specify the directory to use for ROMs.

[Breiztiger]

or you can make directory with rom name and automatic choose the right one when you type --mk1, --jv880 , ...

[nvllsvm]

or you can make directory with rom name and automatic choose the right one when you type --mk1, --jv880 , ...

Being able to specify the folder via an argument is useful on Linux where the application is usually installed to a location where only the root user has write access too.

Ex.

$ pacman -Qql nuked-sc55
/usr/
/usr/bin/
/usr/bin/nuked-sc55
/usr/share/
/usr/share/licenses/
/usr/share/licenses/nuked-sc55/
/usr/share/licenses/nuked-sc55/LICENSE
/usr/share/nuked-sc55/
/usr/share/nuked-sc55/back.data
$ ls -l /usr/share/nuked-sc55
total 4396
-rw-r--r-- 1 root root  794352 May  7 17:39 back.data
-rw-r--r-- 1 root root   32768 Apr 28 19:22 rom1.bin
-rw-r--r-- 1 root root  524288 Apr 28 19:22 rom2.bin
-rw-r--r-- 1 root root    4096 Apr 28 19:22 rom_sm.bin
-rw-r--r-- 1 root root 2097152 Apr 28 19:22 waverom1.bin
-rw-r--r-- 1 root root 1048576 Apr 28 19:22 waverom2.bin