Improve UI for send D2C messages (#391)

1. Fix issue #390 
2. Adjust the location of dummy json tooltip
3. Update the icon of dummy json information icon
4. Update color of information icon in dark/light theme
5. Update color of '*' character in dark theme
6. Remove the arrow of dummy json tooltip
7. Remove input box border in device selector, which is set by VS Code

resources/simulator/index.html

@@ -57,14 +57,14 @@
                         </form-item>
                         <Row :gutter="10">
                             <i-col span="7" style="width: 200px">
-                                <form-item prop="numbers" label="Message(s) per device">
+                                <form-item prop="numbers" label="Message(s) per device" style="text-align: left">
                                     <i-input v-model="formItem.numbers" placeholder=""
                                         @on-change="persistInputs">
 										</i-input>
                                 </form-item>
                             </i-col>
                             <i-col span="10" style="width: 200px">
-                                <form-item prop="interval" label="Interval between two messages">
+                                <form-item prop="interval" label="Interval between two messages" style="text-align: left; width: 200px">
                                     <i-input v-model="formItem.interval" placeholder=""
                                         @on-change="persistInputs" style="padding-top: 1px">
                                         <!-- padding-top=1px: because the ivu-input with append or prepend slot will have -1 px in padding -->
@@ -83,11 +83,11 @@
                                     <radio-group v-model="messageBodyType" @on-change="messageBodyTypeChange">
                                         <Radio label="Plain Text">Plain Text</Radio>
                                         <Radio label="Dummy Json">Dummy JSON
-                                            <Tooltip theme="light" transfer max-width="500" placement="top">
+                                            <Tooltip theme="light" transfer max-width="500" placement="top-start">
                                                 <!-- Set transfer=true, to append the layer in body.
                                           When used in Tabs or a fixed Table column, by adding this property,
                                           Tooltip will not be affected by the parent style, resulting in better results. -->
-                                                <Icon type="ios-information-circle" size="18"></Icon>
+                                                <Icon type="md-information-circle" size="18"></Icon>
                                                 <!-- In the content slot, content should begin from the left,
                                           otherwise unexpected space will be regarded as part of content -->
                                                 <div slot="content">

resources/simulator/main.css

@@ -1,5 +1,9 @@
 .ivu-icon {
-	color: #2d8cf0;
+	color: #007acc;
+}
+
+.vscode-dark .ivu-icon {
+  color: #0e639c
 }
 
 .ivu-radio-group {
@@ -139,5 +143,18 @@ body {
 }
 
 .vscode-dark .ivu-spin-fix {
-  background-color: rgba(60, 60, 60, .9)
+  background-color: rgba(60, 60, 60, .9);
 }
+
+.vscode-dark .ivu-form-item-required .ivu-form-item-label:before {
+  content: '*';
+  color: #f2461b;
+}
+
+.ivu-tooltip-arrow {
+  display: none;
+}
+
+.ivu-select-input {
+  outline: none !important;
+}