Improved Makefile

* Remove "-c" from CFLAGS and hard-code it into the recipe -- CFLAGS
  should be overridable from the command-line but not including "-c"
  should never invoke the linker on object files
* Use real target names for library files instead of phony targets
* Add install and install-shared targets
* Use $(OBJECTS) instead of *.o
* Use .PHONY to properly mark phony targets

Conflicts:
	eval_apply.cpp

Don't think we need to eagerly evaluate numeric values after all, now that we're fully evaluating function args.

Cloning the predicates and loop lists in the control directives inside the function evaluator. Necessary in case they get modified during the in-place evaluation.

Evaluating numeric constants as soon as possible (i.e., at parse time). Should prevent subtle eval bugs later on.

Little tweaks. Some concatenations are still erroneously quoted, but that can be easily worked around for the time being with the 'unquote' built-in.

Redoing the arithmetic. Should fix some erroneous behavior on complex expressions in weird contexts.