Isolated Javascript source from stand-alone HTML file
Add test program and output
'clamp' private key value to harden default curve25519 function and avoid unsafe keys; former behaviour is still available via curve25519_raw for potential use in algorithms that pre-validate the private key.
Rename test.txt to test-output.txt
Create README.md
Update README.md
Update README.md
Rename curve25519.html to curve25519-browser-test.html
Update README.md

Improved documentation a little bit
Update README.md

Corrected key representation
Update README.md

corrected key representation
Update README.md

wording
Yay -- finally the main function is branching-free
Add a benchmark.
Saved some work as patches
Update code embedded in browser test.
When the public key is omitted, use basepoint.
Corrected a comment
Removed unused 'x' arguments, spotted on github by 'liliakai'.
c255lbigintcmp without Math.round, Math.abs

c255lbigintcmp is commented "...tricky to avoid code branching", but it uses Math.round and Math.abs, which could very well have branches in their implementation. We can replace that with bit operations, which will be faster and less branchy.