Improve invalid templates error processing

[slavap]

In my component I have:

@JsProperty @Prop boolean important;

Then in template I'm doing quite often mistake - missing value between quotes:

:important=""

I'm getting error, which is good, but it's not informative:
"SyntaxError: Unexpected token ,"

Uncaught SyntaxError: Unexpected token ,
    at new Function (<anonymous>)
    at $initRenderFunctions_0_g$ (VueComponentOptions.java:109)
    at $setComponentTemplate_0_g$ (VueComponentOptions.java:75)
    at getOptions_5_g$ (MyButtonJsType.java:30)
    at MyButtonFactory_1_g$.init_15_g$ [as init_12_g$] (MyButtonFactory.java:27)
    at get_83_g$ (MyButtonFactory.java:37)
    at lambda$1_33_g$ (MyButtonJsType.java:15)
    at MyButtonJsType$lambda$1$Type_1_g$.get_85_g$ [as get_72_g$] (MyButtonJsType.java:15)
    at getFactory_1_g$ (VueGWT.java:112)
    at getFactory_0_g$ (VueGWT.java:100)
    at new VueGwtWidget_3_g$ (VueGwtWidget.java:35)

Would be nice to have it improved to better explain the error.

[slavap]

@adrienbaron tested in beta6-snapshot, works fine, getting error during compile:
Empty expression in template property binding. If you want to pass an empty string then simply don't use binding: my-attribute=""
[INFO]
[INFO] In expression: :mini=""
[INFO]
[INFO] While processing Node: <jqm-button variant="primary" :mini="" :size="JqmButtonSize.LARGE" @click="counterValue--">
[INFO] Decrease
[INFO]