add fuzzing tests for syntax package, fix issues discovered by fuzzing

Add benchmark to match go stdlib

add more detail about code history to ATTRIB file. fixes dlclark#11

prevent panic with multi-byte unicode bmPrefix that partially match. f…

…ixes dlclark#6

prevent panic when using 2-byte unicode bmPrefix against 3-byte input…

… values. fixes dlclark#5

fix ECMAScript mode -- merge branch 'dop251-ecmascript'

add ReplaceFunc to support MatchEvaluator custom replacement functions. 

fixes dlclark#3

added support for unicode script blocks

update travis CI config