Removed PassThruNode
Added GainNode, which at the moment always has a gain of 1.0
Give GainNode an actual multiplier stage - still 1.0, though
GainNode shouldn't inherit from JackNode - whoops
Move buf vector from GainNode and Node
Added CPP2RB_W_FUNCS_REG
Added adjustable gain to GainNode
Add macros to encapsulate simple Ruby-accessible C++ parameters
Made Node utilize CPP2RB_P macros
Give GainNode proper garbage collection - need to figure out how to encapsulate it into CPP2RB_P macros