Basic launch-option functionality

[Dassu]

Added some basic launch options

A ROM file can be specified to load when the GUI is finished loading, contain in quotes if there are spaces in the filename

• -filename [ROM filename]

Song ID is assumed decimal. If it has leading zeros it will be read as hexadecimal

• -songid [song index]

An Engine must be specified using one of these launch options

• -mp2k
• -dse
• -alphadream
• -sdat

This is an example of working launch options:

-filename "C:\Users\Dassu\GBA\FFTA.GBA" -songid 24 -mp2k

Sorry if it's a bit messy. Just wanted to throw something together after reading this issue: #81

[FEBuilderGBA]

I confirmed that your optional features work properly.
Thank you for implementing the option.

"VG Music Studio.exe" -filename "foo.gba" -mp2k -songid 123

The songid 123 was played correctly.
It's perfect.
Thank you.