Fix maybe-uninitialized warning
Organize method and protocol source files into distinct source directories
Unify duplicate code in xsalsa20-poly1305 and aes128-gcm methods
Allow using libsodium instead of NaCl

As libsodium has some strange include files (like a version.h), we try to use
absolute include paths whenever possible in fastd now and rename our generated
headers.
Handle methods as strings
Drop compatiblity code for fastd 0.4
handshake: get_method() code simplification
config: iterate over configured methods only in configure_method_parameters()
Generate method list automagically
Rename fastd_parse_method_name to fastd_method_get_by_name
Correctly terminate method list
Separate ec25519-fhmqvc into multiple source files
ec25519-fhmqvc: add secure_handshake helper function
Add fastd_handshake_add_zero function
ec25519-fhmqvc: include either T or TLV_MAC in handshake finish, but not both
ec25519-fhmqvc: get rid of duplicate code in shared handshake key generation
Don't delay initial handshakes when no peer limit is set
Change error subcode for unsupported method from method name to method list

When two peers don't support a common method, fastd should notice this in the
list stage, so the method list subcode is correct.

The method name subcode was a legacy of the 0.4 compatiblity code.
Rename session_init to session_init_compat to prepare for the upcoming new key derivation scheme
ec25519-fhmqvc: some more handshake refactoring