Drawj2d 0.6.1 released

This release adds support for custom colours and adds more examples to the function reference.

Changes:
- command pen enhanced to accept any colour by rgb hex values. Brown colour defined.
- new command stat.tip
- command geom.distance enhanced
- command fillrect enhanced
- commands geom.angle/anglerad enhanced
- command dot modified: larger that point.
- new command shortcuts geom.v, geom.abs, geom.dist, stat.dist
- commands force/force2 modified: not drawing if the abs force value is zero.
- commands label/texlabel enhanced.
- fix command texdimlinerel: typesetting issue
- documentation: more examples