Allow Verts to be adjusted with Tweak Tool

[carter2422]

After creating the initial contour strokes you invariably need to tweak the position of some vert within the mesh. It would be great to allow the user to do this before committing the retopo mesh.

Ideally switching to the Tweak Tool would let the user move individual vertices around with a smoothing-like brush. Tweaking a vertex would place the loop into a manual state, rather than dynamic, such that it could no longer be modified as part of a stroke.

[vxlcoder]

suggestion: use the terms "manual" and "dynamic", rather than "lock" and "unlock" (?). "lock" implies that it cannot be adjusted further.

[vxlcoder]

related to this, a relax verts feature could position the vertices to make quads more regular.

[carter2422]

Ah yes, that's much better wording. Updated issue.