Implement SCM hooks in C -- not yet used.

[Derek Atkins]

Log Message:
-----------
Implement SCM hooks in C -- not yet used.

	* src/engine/gnc-hooks*:
	  First attempt at implementing SCM hooks in C.
	* src/engine/Makefile.am:
	  Handle new (private) header file, gnc-hooks-scm.h

Tags:
----
gnucash-gnome2-dev

Modified Files:
--------------
    gnucash:
        ChangeLog
    gnucash/src/engine:
        Makefile.am
        gnc-hooks.c
        gnc-hooks.h

Added Files:
-----------
    gnucash/src/engine:
        gnc-hooks-scm.h