Added support for arbitrary interface shapes using the pst-intersect package.
Require pstricks version 2.53 for the cubic spline interpolation
Added \parabolicmirror as first component using this feature.
Probably this will become a new major version 5.0
Some minor corrections
Merge remote-tracking branch 'origin/master' into arbifc

Conflicts:
	pst-optexp.dtx
	pst-optexp.ins
Merge remote-tracking branch 'origin/arbifc'
Don't generate a TDS-compliant archive for uploading.
Added an example using arbitrary line interface.
Fixed a problem with pst-intersect v0.4