[commit] Rename .eval -> .exec, add new .eval.

[Doug Evans]

fyi, I checked this in.

2009-08-17  Doug Evans  <dje@sebabeach.org>

	Rename .eval -> .exec.  Add new .eval.
	* pmacros.scm (-pmacro-built-exec): Renamed from -pmacro-builtin-eval.
	(-pmacro-builtin-eval): New function.
	(pmacros-init!): Add .exec.
	* doc/pmacros.texi: Update, .exec -> .eval.  Document new .eval.
	* testsuite/location-1.test: Update.
	* testsuite/pmacros-1.test: Add test for .eval.

The previous definition of .eval was inconsistent with uses in Scheme
for no good reason so I renamed it to .exec.