Essential changes:

• security bugfix in Go bindings
• run-time switch in portable build
• no-std support [exercised with limited stack size of 56K]
• serde support
• blst_miller_loop_n interface, with parallelized Rust and Go counterparts
• optional blst_fr_pentaroot subroutine
• Emscripten bindings
• hardened security on non-asm platforms