Force phony targets to build (even if file exists)

This is a convenience makefile only,
files if they exist by accident shouldn't ever be used.
Fix T42972: fcurve lasso select crash
RNA Object.matrix_local: Add a big warning this matrix is only relative to parent object.

So 'advanced' parenting like e.g. bones or vertices need further processing
to get a real parent-relative matrix...
Fix T42961: GPencil - Refactor object/scene data behaviour

D937 with minor edits (whitespace only)

@aligorith, I double checked everything runs smoothly, blame me if I missed something ;). Sorry for just taking the initiative and committing without talking to you, but I wasn't able to catch you the last days. This should be fixed before the release IMHO, but I don't think it's important enough to be committed during BCon5, so sorry again, but hopefully everything is okay :)
Fix T42973: Render viewport not updating when switching materials in Outliner

For now, do as RNA material update functions - tag object for update too.
GPencil: Correction to rB071ec918f4cd

* correct API convention: in rB071ec918f4cd gp_draw_data drew mulitple data blocks, I added gp_draw_data_all which now calles gp_draw_data multiple times (if needed). This follows our normal convention, e.g. see UI_panel_category_draw_all
* Draw scene data first, users may expect it like this

Points raised by @aligorith, thanks for this!
Merge branch 'master' into sticky_keys