Security fixes

I did a fast search and I found 3 security fixes missed.
These patches should fixes these security bugs:
- CVE-2013-4627
- CVE-2013-4165
- CVE-2013-5700

Other details here:
https://en.bitcoin.it/wiki/Common_Vulnerabilities_and_Exposures
I hope that are all missed security fixes.

I did a fast build test and seems working but probably other tests are needed before use them production sistems.