fix [#34490] Copy and paste floating point number fields losses precision
- copy now gets up to 6 decimal places
- copy and UI float button editing now strip zeros: 1.000 -> 1.0


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@55005 954f8c5b-7b00-dc11-b283-0030488c597c