Update README.md

correct spelling of "exert"
Merge pull request #106 from EagleEyeJohn/patch-1

Update README.md
Don't run travis against master (phpng)
reduce the struct size by 8 byte on 64 bit
reduce the struct size by 8 byte on 64 bit
reduce the struct size by 8 byte on 64 bit
reduce the struct size by 8 byte on 64 bit
reduce the struct size by 8 byte on 64 bit
reduce the struct size by 8 byte on 64 bit
fix conditions

substraction from an unsigned
align 4 byte to the start of the word
remove useless casts and checks
reduce struct sizes by 8 bytes each on 64 bit
reduce struct size by 8 byte on 64 bit
reduce struct size by 8 byte on 64 bit
better way to zero away sensitive data

memset could be optimized away by the compiler
fix possible pointer truncation
Fix bug #111 (compile error without ZEND_SIGNALS)
avoid repeated strlen() usage
reduce struct size by 8 bytes on 64 bit