OSC: support int or float for arguments for which either could be used

[aalex]

MapMap expects:

• integers for ID;
• floats values, such as opacity.

Some software send only floats, no integers. It could be handy to allow:

• floats instead of integers for ID
• int instead of float for values, such as opacity.

[aalex]

Waiting for #352 - since we'll move to another OSC library.

[skankerror]

Which is often used and encouraged in osc servers is the integration of the ID in the path, for example /mapmap/paint/1/opacity f 0.8
This could make mapmap more easily controled by software like score.

[aalex]

We did switch to OscPack.