Smash out monero-bulletproofs

Removes usage of dalek-ff-group/multiexp for curve25519-dalek.

Makes compiling in the generators an optional feature.

Adds a structured batch verifier which should be notably more performant.

Documentation and clean up still necessary.

coins/monero/generators/Cargo.toml

@@ -37,7 +37,6 @@ std = [
   "subtle/std",
 
   "sha3/std",
-  "curve25519-dalek/precomputed-tables",
 
   "group/alloc",
   "dalek-ff-group/std",