Enable to rename components with non-English characters

The current internationalization framework doesn't allow to rename
component to something other than English. I changed the identifier
regex and it allows anything but no empty or whitespace.  The regex
for the project name remains unchanged.

Change-Id: I7923151505129791ee575f51992a3418b4677014
Rename runtime->string in runtime.scm

Rename runtime->string in runtime.scm so as to not shadow the Kawa
version.

Change-Id: I17d3896b49c927ce1cbd88036b0e070e08ef669b