[Feature Request] Gamepad button remapping in RPG_RT.ini and command line options

[donmor]

Extremely useful when there's a game requiring special keys to play with, Yume Nikki for example.

An example:

[Controller]
; Use both Dpad and Lstick as direction keys, A/X for Z/X, 1/3/5/9/Reset mapped to L/R/Y/B/Back
Btn_Up="a7-,a1-"
Btn_Down="a7+,a1+"
Btn_Left="a6-,a0-"
Btn_Right="a6+,a0+"
Btn_Actions="b0"
Btn_Cancel="b2"
Btn_1="b4"
Btn_3="b5"
Btn_5="b3"
Btn_9="b1"
Btn_Reset="b6"

• Events are named as Btn_[Up,Down,Left,Right,Actions,Cancel,PgUp,PgDn,Shift,1,2,3,4,5,6,7,8,9,0,+,-,*,/,.,FF3x,FF10x,DebugGoThrough,DebugFps,DebugLog,Fullscreen,Zoom,Screenshot,DebugMenu,DebugAbort,DebugSave,Reset]
• Each event can be triggered by multiple buttons, separated by , in ini file
• Gamepad buttons are named b*(for buttons) or a*+/-(for axes)
• Some axes and buttons are aliased to match xinput layout:
  • a0-->X-
  • a0+->X+
  • a1-->Y-
  • a1+->Y+
  • a2-->RX-
  • a2+->RX+
  • a3-->RY-
  • a3+->RY+
  • a4-->Z-
  • a4+->Z+
  • a5-->RZ-
  • a5+->RZ+
  • a6-->HAT0X-
  • a6+->HAT0X+
  • a7-->HAT0Y-
  • a7+->HAT0Y+
  • b0->A
  • b1->B,
  • b2->X,
  • b3->Y,
  • b4->L,
  • b5->R,
  • b6->BACK,
  • b7->START,
  • b8->MODE,
  • b9->L3,
  • b10->R3,
• Configurations can be placed in RPG_RT.ini in game directory, global ini (Raised by #2802), or in command line option: --controller="Btn_Up:a7-,a1-;Btn_Down:a7+,a1+;Btn_Left:a6-,a0-;Btn_Right:a6+,a0+;Btn_Actions:b0;Btn_Cancel:b2;Btn_1:b4;Btn_3:b5;Btn_5:b3;Btn_9:b1;Btn_Reset:b6"
• Use the default mapping by #2752 when no mapping defined, and disable undefined events if any mapping defined

Player platform:

Windows, Linux, Darwin, ...(other PCs)