add options marker and markeredgecolor to point2d
add additional marker information to plot()
fix documentation for scatter_plot and points

1. Add documentation about the available options to point() documentation
2. Remove list of markers from scatter_plot documentation, and
   refer to plot() instead
merge develop (sage-6.2) on to current ticket
trac #7232 warning if camera and observed point coincide in tachyon scenes
Implement tensor product of linear functions and free modules
Add a parent for MIPVariables
Make the parent of MIPVariables a singleton
Enable p.<x> = MixedIntegerLinearProgram() syntax
Rebasing on 6.3.rc1

Conflicts:
	src/sage/plot/plot3d/tachyon.py
trac #7232 oops, mistake in merge, now corrected
Match x_i print order

This commit makes vector-valued linear functions print in the same
order as normal linear functions.
trac #16797: is_difference_matrix
Symbolic (in)equality involving linear tensors
trac #16797: Fit with the current definition until we can change everything at once
trac #16797: int * and ** instead of Python list
trac #16797: change int to int * in a malloc
trac #16797: better malloc + better error msg
trac #16797: More compact mallocs
trac #16797: Reorder the arguments to copy is_orthogonal_array