Made double literals float literals in MarPanning
Fixed type conversion errors in MarGrid2
scripting: implement prototype definition and re-use
scripting: implement realvec as control value
scripting: change root system when applying controls to prototype
scripting: more verbose error messages
scripting: improve control path syntax

* Get rid of the requirement for '@' at beginning of path

* Allow remote paths at left-hand-side of control assignment
scripting: umm... positive numbers are only half of the world

Support the other half of the big number divide.
scripting: include <algorithm> as appropriate
script: prototype mathematical expressions as control values
scripting: fix operator precedence

Let '*' and '/' precede '+' and '-'.
scripting: expressions: avoid hardcoded result type
scripting: operation processor: implement clean-up routine
scripting: destroy operation processor together with controlled MarSystem

This calls for a way to attach MarSystems to other MarSystems
so that the attached ones are deleted with those that they attach to.

In future, we could think of tighter integration of control expression
processing with the MarControl system itself, so as to avoid using
a specialized MarSystem for that purpose.
scripting: allow any order of control and child-actor definitions
scripting: prototype conditional state

For example:
Series {	when (true) { inSamples = (/other/onSamples * 2) } }
scripting: disallow "+" at beginning of conditional state definitions
scripting: implement comparison operators
scripting: states: support remote destination control paths
scripting: state processor: support inversion