Does not deal with an 'invisible times' unicode character \u2062

(I have expanded the string to show it's location, but normally it would be hidden !)

Input string is `"E=m\u2062c^2"`

``` c#
Call_LaTeX_To_Expression_Einstein_Equation Failed: TexDotNet.TexLexerException : Illegal character '⁢'.
TexDotNet.TexLexerException : Illegal character '⁢'.
Charcter position: 4
Source text: ⁢
at TexDotNet.TexLexer.ScanShortSymbol(TrackedTextReader reader, Object& value) in Syntax\TexLexer.cs:line 163
at TexDotNet.TexLexer.Tokenise(TrackedTextReader reader)+MoveNext() inSyntax\TexLexer.cs:line 71
at TexDotNet.TexUtilities.ForceMoveNextIncludeFormatting(IEnumerator`1 tokenStream) in TexUtilities.cs:line 71
at TexDotNet.TexUtilities.ForceMoveNext(IEnumerator`1 tokenStream) in TexUtilities.cs:line 65
at TexDotNet.TexParser.ParseRawValueOptional(IEnumerator`1 tokenStream, ParserState& state) in Semantics\TexParser.cs:line 307
at TexDotNet.TexParser.ParseValueOptional(IEnumerator`1 tokenStream, ParserState& state) in Semantics\TexParser.cs:line 279
at TexDotNet.TexParser.ParseIndexedValueOptional(IEnumerator`1 tokenStream, ParserState& state) in Semantics\TexParser.cs:line 259
at TexDotNet.TexParser.ParseFactorialValueOptional(IEnumerator`1 tokenStream, ParserState& state) in Semantics\TexParser.cs:line 234
at TexDotNet.TexParser.ParseTermOptional(IEnumerator`1 tokenStream, ParserState& state, Boolean isSubTree) in Semantics\TexParser.cs:line 187
at TexDotNet.TexParser.ParseTermOptional(IEnumerator`1 tokenStream, ParserState& state) in Semantics\TexParser.cs:line 182
at TexDotNet.TexParser.ParseTerm(IEnumerator`1 tokenStream, ParserState& state) in Semantics\TexParser.cs:line 174
at TexDotNet.TexParser.ParseSignedTerm(IEnumerator`1 tokenStream, ParserState& state) in Semantics\TexParser.cs:line 168
at TexDotNet.TexParser.ParseExpression(IEnumerator`1 tokenStream, ParserState& state, Boolean isSubTree) in C:\Users\sogscx\source\repos\RulesEngine\LaTeX2ExpTree2MathML\Tex.Net\Semantics\TexParser.cs:line 135
at TexDotNet.TexParser.ParseExpression(IEnumerator`1 tokenStream, ParserState& state) in Semantics\TexParser.cs:line 129
at TexDotNet.TexParser.ParseFractionalExpression(IEnumerator`1 tokenStream, ParserState& state) in Semantics\TexParser.cs:line 111
at TexDotNet.TexParser.ParseRelationalExpression(IEnumerator`1 tokenStream, ParserState& state, Boolean isSubTree) in Semantics\TexParser.cs:line 51
at TexDotNet.TexParser.ParseRelationalExpression(IEnumerator`1 tokenStream, ParserState& state, Boolean isSubTree) in Semantics\TexParser.cs:line 104
at TexDotNet.TexParser.ParseRelationalExpression(IEnumerator`1 tokenStream, ParserState& state) in Semantics\TexParser.cs:line 45
at TexDotNet.TexParser.Parse(IEnumerator`1 tokenStream) in Semantics\TexParser.cs:line 29
at TexDotNet.TexUtilities.CreateParseTree(IEnumerator`1 tokenStream) in TexUtilities.cs:line 58
at TexDotNet.TexUtilities.CreateParseTree(String expression) in TexUtilities.cs:line 52
at TexDotNet.TexUtilities.CreateExpressionTree(String expression) in TexUtilities.cs:line 42
at LaTeX2ExpTree2MathML.LaTeX2MathML.ConvertToExpressionTree(String inputLaTeX) in \LaTeX2MathML.cs:line 34
```