Mirror function doesn't work with custom side labels

[joji2468ng]

swapSideLabel(name) function is hard coded to work with capital L and R. This is where the trouble is happening.

This issue has been already fixed in the pull request #285 (comment)

The fix involves swapping the side label in control names based on the rig’s naming convention.
It should handle dynamically by using guide data’s naming patterns to identify and swap the current side label,
e.g., from ‘L’ to ‘R’ and vice versa."

Reported:
http://forum.mgear-framework.com/t/control-mirroring-broken/3687