Add a custom button to entity ribbon

<RibbonDiffXml>
  <CustomActions>
    <CustomAction Id="org.button.Form.CustomAction" Location="Mscrm.Form.account.MainTab.Save.Controls._children" Sequence="1">
      <CommandUIDefinition>
        <Button Id="org.button.Form.WhatifButton" Command="org.button.Command" LabelText="What If Analysis" ToolTipTitle="Launch" ToolTipDescription="30 Years What If Analysis" TemplateAlias="o1" Image16by16="$webresource:neu_button16x16" Image32by32="$webresource:neu_button32x32" />
      </CommandUIDefinition>
    </CustomAction>
  </CustomActions>
  <Templates>
    <RibbonTemplates Id="Mscrm.Templates"></RibbonTemplates>
  </Templates>
  <CommandDefinitions>
    <CommandDefinition Id="org.button.Command">
      <EnableRules>
      </EnableRules>
      <DisplayRules>
      </DisplayRules>
      <Actions>
        <Url Address="$webresource:helloworld.html" PassParams="true" WinMode="0" WinParams="width=1100,height=760,toolbar=no,location=no,resizable =yes" />
      </Actions>
    </CommandDefinition>
  </CommandDefinitions>
  <RuleDefinitions>
    <TabDisplayRules />
    <DisplayRules/>
    <EnableRules />
  </RuleDefinitions>
  <LocLabels />
</RibbonDiffXml>