This enables testing overflow is correctly encoded in the recid, and
likely triggers more edge cases.
Also introduce a Sage script to generate the parameters.
Most of the codebase correctly used short-cutting to avoid calling
_is_zero on possibly incompletely initialized elements, but a few
places were missed.
Identifiers starting with an underscore and followed immediately by a capital letter are reserved by the C++ standard.
The only header guards not fixed are those in the headers auto-generated from java.
Make sure we clear the nonce data even if the nonce function fails (it may have written partial data), and call memset only once in the case we iterate to produce a valid signature.
There are now 2 encoding formats supported: 64-byte "compact" and DER.
The latter is strict: the data has to be exact DER, though the values
inside don't need to be valid.
Libtool will do the right thing and use whatever is available
based on --enable-shared/--enable-static.
This also means that some of the things we build actually
test the dynamic library.
