API clean up (part 2), plus misc changes and improvements.

- Rename regpkgs_dictionary to regpkgdb_dictionary to better describe what is is.
- Change some funcs in plist.c to return a boolean rather than int.
- Hide more internal funcs off the API.
- Simplify xbps_repository_update_pkg() and remove its second arg.
- Hide implementation details in xbps_repository_pool, now to iterate over the
  pool you have to use xbps_repository_pool_foreach and its struct
  repository_pool_index.
- Introduce xbps_{init,end}, to initialize/destroy some stuff in the library.
- Introduce xbps_dbg_printf to printf stuff for debugging purposes.
- xbps-{bin,repo}:  added -d arg to enable debugging output.
- Before checking if a config file needs to be installed or such, check that
  package contains the "conf_files" array.
- Remove obsolete dirs as well while updating packages.
- If transaction dictionary is ready remove the "missing_deps" array.

Bump XBPS_RELVER to 20101118.

--HG--
rename : lib/regpkgs_dictionary.c => lib/regpkgdb_dictionary.c

lib/fexec.c

@@ -80,7 +80,7 @@ pfcexec(const char *path, const char *file, const char **argv)
 				_exit(127);
 		}
 
-		(void)execvp(file, __UNCONST(argv));
+		(void)execv(file, __UNCONST(argv));
 		_exit(127);
 		/* NOTREACHED */
 	case -1:
@@ -138,7 +138,7 @@ vfcexec(const char *path, int skipempty, const char *arg, va_list ap)
 	return retval;
 }
 
-int
+int HIDDEN
 xbps_file_exec(const char *arg, ...)
 {
 	va_list	ap;
@@ -151,7 +151,7 @@ xbps_file_exec(const char *arg, ...)
 	return result;
 }
 
-int
+int HIDDEN
 xbps_file_exec_skipempty(const char *arg, ...)
 {
 	va_list	ap;
@@ -164,7 +164,7 @@ xbps_file_exec_skipempty(const char *arg, ...)
 	return result;
 }
 
-int
+int HIDDEN
 xbps_file_chdir_exec(const char *path, const char *arg, ...)
 {
 	va_list	ap;