* add if conditions
* update v-if conditional
* update test
* update test case
* add test case
* update if conditions
* update walkThroughConditionsBlocks
* update v-elseif
* update v-once with v-elseif test case
* update style with v-elseif
* update flow type
* fixed if/for/else render update bug
* added v-else with v-if test
* added v-if test with v-else and v-for
* removed unnecessary elseBlock detect in optimizer