* examples/search-ns.scm: a basic tool to search namespaces.
* examples/identity.scm: a basic tool to list egos.
* examples/identity-bis.scm: idem, but using `start-identity-lookup`.
* fs/uri.scm: `wrap-uri` throws an `invalid-arg` exception when given a
null pointer.
* tests/uri.scm: c.f. ↑
* configuration.scm: add `configuration-value-set?`.
* identity.scm: add `ecdsa-public-key->string`.
* examples/download.scm: a loose `gnunet-download' clone.
* system/foreign/unions.scm: add the possibility to specify #f as a
union variant to get a padding of the
size of the union.
* gnu/gnunet/fs/progress-info.scm: just adapted to the modification to
unions.scm.
* gnu/gnunet/fs/uri.scm: add a few utility functions: `parse-uri' and
`uri-file-size'.
* gnu/gnunet/fs/fs.scm: add `start-download` and `stop-download`.
* examples/search.scm: echo changes in the API;
* gnu/gnunet/common.scm: add ecdsa-public-key? and string->data-pointer;
* gnu/gnunet/fs.scm: replace search-service-open with open-filesharing-service,
replace start-ksk-search with start-search;
* gnu/gnunet/fs/uri.scm: add make-sks-uri-pointer and make-sks-uri;
* tests/uri.scm: add tests for make-sks-uri-pointer and make-sks-uri.