Fixed support for symbols ID which are not numbers (#98)

* Support for ID that are numbers

https://stackoverflow.com/a/20306218/532695

* Fixed missing )

* fixed the attribute name

* Raise an exception if a symbol is not found

Prevent from crashing in the case we specified a wrong fragment for a symbol name.
For instance an svg has a symbol abcd, if I specified `someUrl/my.svg#defg` it will fail using the onSVGFail error emitter.

src/inline-svg.directive.ts

@@ -109,13 +109,18 @@ export class InlineSVGDirective implements OnInit, OnChanges, OnDestroy {
       .subscribe(
         (svg: SVGElement) => {
           if (this._isUrlSymbol(this.inlineSVG)) {
-            const symbolId = '#' + this.inlineSVG.split('#')[1];
-
+            const symbolId = this.inlineSVG.split('#')[1];
+            const symbolSelector = '#' + symbolId;
             const elSvg = this._renderer.createElement('svg', 'svg');
-            this._renderer.appendChild(elSvg, svg.querySelector(symbolId));
+            const symbol = svg.querySelector("[id='"+symbolId+"']");
+            if (!symbol){
+              this._fail('No symbol:'+symbolId+' found');
+              return;
+            }
+            this._renderer.appendChild(elSvg, symbol);
 
             const elSvgUse = this._renderer.createElement('use', 'svg');
-            this._renderer.setAttribute(elSvgUse, 'href', symbolId, 'xlink');
+            this._renderer.setAttribute(elSvgUse, 'href', symbolSelector, 'xlink');
             this._renderer.appendChild(elSvg, elSvgUse);
 
             this._processSvg(elSvg);