Fix multiple-free problem.

Use of static constructors in headers cause the constructors/destructors to be
run in each compilation unit that includes the headers.  The multiple
constructors runs are leaks, the multiple destructor runs are multiple-frees
at program exit time.  These string constructors can instead use const char*
with little impact on the methods that reference them.

Common/Include/commandArgUtil.h

@@ -24,12 +24,12 @@ namespace Microsoft { namespace MSR { namespace CNTK {
 static const std::string::size_type npos = (std::string::size_type) -1;
 
 // These are the constants associated with the "ResolveVariables" method.
-static const std::string openBraceVar = "$";
-static const std::string closingBraceVar = "$";
-static const std::string forbiddenCharactersInVarName = ",/<>?;':\"[]{}\\|!@#%^&*()+=~` \t\n";
-static const std::string forbiddenCharactersInVarNameEscapeWhitespace = ",/<>?;':\"[]{}\\|!@#%^&*()+=~` \\t\\n";
-static const std::size_t openBraceVarSize = openBraceVar.size();
-static const std::size_t closingBraceVarSize = openBraceVar.size();
+static const char* openBraceVar = "$";
+static const char* closingBraceVar = "$";
+static const char* forbiddenCharactersInVarName = ",/<>?;':\"[]{}\\|!@#%^&*()+=~` \t\n";
+static const char* forbiddenCharactersInVarNameEscapeWhitespace = ",/<>?;':\"[]{}\\|!@#%^&*()+=~` \\t\\n";
+static const std::size_t openBraceVarSize = strlen(openBraceVar);
+static const std::size_t closingBraceVarSize = strlen(closingBraceVar);
 
 // Trim - trim white space off the start and end of the string
 // str - string to trim
@@ -991,23 +991,23 @@ class ConfigParameters: public ConfigParser, public ConfigDictionary
         while (start != std::string::npos)
         {
             // search for whitespace or closing brace.
-            end = newConfigLine.find_first_of(closingBraceVar + forbiddenCharactersInVarName,
+            end = newConfigLine.find_first_of(std::string(closingBraceVar) + forbiddenCharactersInVarName,
                                               start + openBraceVarSize);
 
             // ensure that a closing brace exists for every opening brace.
             // Also ensure that there is no whitespace between the opening and closing braces.
             if (end == std::string::npos)
             {
                 RuntimeError("\"%s\" found without corresponding closing \"%s\": %s:%s",
-                             openBraceVar.c_str(), closingBraceVar.c_str(),
+                             openBraceVar, closingBraceVar,
                              m_configName.c_str(), newConfigLine.c_str());
             }
 
             if (newConfigLine[end] != '$')
             {
                 RuntimeError("Forbidden characters found between \"%s\" and \"%s\".  Variable names cannot any of the following characters: %s. %s:%s",
-                             openBraceVar.c_str(), closingBraceVar.c_str(),
-                             forbiddenCharactersInVarNameEscapeWhitespace.c_str(),
+                             openBraceVar, closingBraceVar,
+                             forbiddenCharactersInVarNameEscapeWhitespace,
                              m_configName.c_str(), newConfigLine.c_str());
             }