Update effective version to 3.0

* GUILE-VERSION: Bump version to 2.3.0, and effective version to 3.0.
* .gitignore:
* README:
* doc/guile.1:
* doc/ref/api-evaluation.texi:
* doc/ref/api-options.texi:
* doc/ref/guile-invoke.texi:
* doc/ref/libguile-foreign-objects.texi:
* doc/ref/libguile-parallel.texi:
* doc/ref/srfi-modules.texi: Update to 3.0.
* libguile/_scm.h (SCM_OBJCODE_MAJOR_VERSION):
(SCM_OBJCODE_MINIMUM_MINOR_VERSION, SCM_OBJCODE_MINOR_VERSION): Bump
bytecode version for fallback path.
* libguile/loader.c: Update to avoid loading version 2.2 bytecode
files.
* meta/guile-3.0-uninstalled.pc.in:
* meta/guile-3.0.pc.in: Rename.
* module/system/vm/assembler.scm (*bytecode-major-version*):
(*bytecode-minor-version*): Write the new bytecode version.

meta/Makefile.am

@@ -77,7 +77,7 @@ substitute =									\
 	 -e "s|[@]guild[@]|$$guild|g"						\
 	 -e "s|[@]installed_guile[@]|$$installed_guile|g"
 
-# Substitutions for dependencies that appear in 'guile-2.0.pc'.
+# Substitutions for dependencies that appear in 'guile-3.0.pc'.
 dependency_substitutions =				\
   -e "s|[@]BDW_GC_CFLAGS[@]|$(BDW_GC_CFLAGS)|g"		\
   -e "s|[@]BDW_GC_LIBS[@]|$(BDW_GC_LIBS)|g"		\