Fix Key label positioning bug on Firefox

Closes #90

src/components/svg/keys/svg-keyboard-key/svg-keyboard-key.component.html

@@ -5,8 +5,7 @@
 <svg:g [ngSwitch]="labelType"
         [attr.font-size]="19"
         [attr.font-family]="'Helvetica'"
-        [attr.fill]="'white'"
-        style="dominant-baseline: central">
+        [attr.fill]="'white'">
     <svg:g svg-keystroke-key *ngSwitchCase="enumLabelTypes.KeystrokeKey"
             [height]="height"
             [width]="width"

src/components/svg/keys/svg-keyboard-key/svg-keyboard-key.component.scss

@@ -0,0 +1,3 @@
+:host /deep/ text {
+    dominant-baseline: central;
+}

src/components/svg/keys/svg-keyboard-key/svg-keyboard-key.component.ts

@@ -26,7 +26,8 @@ enum LabelTypes {
 
 @Component({
     selector: 'g[svg-keyboard-key]',
-    template: require('./svg-keyboard-key.component.html')
+    template: require('./svg-keyboard-key.component.html'),
+    styles: [require('./svg-keyboard-key.component.scss')]
 })
 export class SvgKeyboardKeyComponent implements OnInit, OnChanges {
     @Input() id: string;