Math parser should allow apostrophe in variable name.

Apostrophe is actively used in French language.

--HG--
branch : develop

src/libs/qmuparser/qmudef.h

@@ -94,7 +94,7 @@ QT_WARNING_DISABLE_GCC("-Wattributes")
 inline QString NameRegExp()
 {
     //Same regexp in pattern.xsd shema file. Don't forget synchronize.
-    return QStringLiteral("^([^0-9*/^+\\-=\\s()?%:;!.,`'\"]){1,1}([^*/^+\\-=\\s()?%:;!.,`'\"]){0,}$");
+    return QStringLiteral("^([^0-9*/^+\\-=\\s()?%:;!.,`'\"]){1,1}([^*/^+\\-=\\s()?%:;!.,`\"]){0,}$");
 }
 
 QT_WARNING_POP

src/libs/qmuparser/qmuformulabase.cpp

@@ -69,7 +69,7 @@ void QmuFormulaBase::InitCharacterSets()
                               << "ЭųįҶرҲеԷňعθҺнԿفπÂхՇψÊэšՏÒUəÚѝŻşҤӑâeէŐımկòuշÕúտŔ";
 
     // Defining identifier character sets
-    DefineNameChars(QStringLiteral("0123456789_@#") + symbols.join(""));
+    DefineNameChars(QStringLiteral("0123456789_@#'") + symbols.join(""));
     DefineOprtChars(symbols.join("") + QStringLiteral("+-*^/?<>=!$%&|~_"));
 }