elements: Global variable whether we are running on elements

Using a global variable is a bit lazy, but weaving the network type through
the entire stack is a daunting task. Maybe we can make that happen at a later
stage.

Most of the changes in `chainparams.c` are just formatting the
`genesis_blockhash` a bit nicer (`clang-format` to the rescue).

Signed-off-by: Christian Decker <decker.christian@gmail.com>

common/utils.c

@@ -6,6 +6,7 @@
 
 secp256k1_context *secp256k1_ctx;
 const tal_t *tmpctx;
+bool is_elements = false;
 
 char *tal_hexstr(const tal_t *ctx, const void *data, size_t len)
 {