[Bf-committers] edge slide bug + cause

[Antony Riakiotakis]

There is a bug in current edge slide tool, where if you have automere
on and try to do edge slide with a factor of 0, the edge disappears.
What actually happens is that the sliding edge gets merged with the
temporary faces that are created for data projection, which are later
deleted during cleanup. These temporary faces should either be deleted
before automerging somehow (data cleanup is after transform cleanup
unfortunately), or somehow neglected by the bmesh double vertex detect
operator, without influencing other tools.