Merge pull request #4 from puritys/master

Fix php warning, when render a index zero of array
better logic on var name checking. add 1 new test for {{0}} . But, {{0}} is not official supported by handlebars.js [Cause Parsing Error]
update README to adopt a plan
align with handlebars 1.3. support both {{@index}} and {{@key}} when {{#each an_object}}
update history
refine code for useVar internal flag. stop using array on it.
try to support advvar (not done)
add new doc for FLAG_JSQUOTE (code not done)
support exact same single quote encoded output with handlebars.js
update history
merge master
fix wrong single quote encoding
Merge branch 'master' into advanced_varname
try to support advvar when in useVar compile time. not tested, no error handling now
add advanced variable name checking in scan() stage
add test for error case
add example for small test script
now can report more than 1 error in template when compile()
add more error varname test
now detect advanced variable name error in scan() , add more test case in test/error.php