1. Allow AddressDollop() to tell Zipr whether
the dollops should be coalesced. Defaults to true.

2. Allow the plugin to retarget a pin.

Give the source address for the instruction
that is targeting the dollop to be placed. This
will give another signal to placement plugins
to help them make a decision.

Let a plugin tell us about where to plop a dollop.
This change includes a

1. utils namespace with a function to calculate
the worst case instruction size.
2. Dollop_t type that can be used to describe
and pass around a dollop.

1. Add support for plugins to call certain
Zipr_t functions. This meant making a class
that is Zipr_t and then converting the actual
implementation to a subclass (ZiprImpl_t). The
Zipr_t goes in the zipr_sdk.

2. Ask all plugins about each instruction
and determine whether there are any takers
for plopping.

3. When plopping an instruction, consider
whether or not a plugin asked to do the plopping.
If so, let it do the work.