Strip trailing zeros from floats in map writer.
Fixed a crash in vertex tool.
Merge branch 'NewArchitecture' of github.com:kduske/TrenchBroom into NewArchitecture
Fixed a couple of bux in vertex code.

- Sometimes vertices would become unmoveable because the handle manager stored them as floats.
- Certain vertex moves were disallowed because they would lead to colinear triangles. These are now allowed and the colinear triangles get deleted.
Allow editing the entity classname property.