fixes and improvements for hstshijack

[buffermet]

Bug fixes

• whitelisting bug fixed (2 bad variable references)
• custom payload preloading bug fixed where it would overwrite core payload
• payload injection bug fixed where dollar signs would insert matches

New features

• set 3 more insecure headers to prevent browsers from caching
• upgraded form-phisher.js (binds to XMLHttpRequest)
• upgraded form-phisher.js (always whitelists when a password is submitted)
• renamed form-phisher.js to keylogger.js
• upgraded sslstrip.js (binds to XMLHttpRequest)
• upgraded sslstrip.js (strips more elements)
• more consistent callback request dumps
• callback requests are now dumped even if the host was whitelisted for that client
• configured dns.spoof module & added keylogger.js in caplet file
• added more info and examples to README