Be more consistent about using .data() for gettng C arrays

It's safer than &var[0] as that will invoke undefined behaviour if var
is empty.

src/api/helpers/text.cpp

@@ -143,8 +143,8 @@ std::wstring ToWinWide(const std::string& str) {
                       0,
                       str.c_str(),
                       static_cast<int>(str.length()),
-                      &wstr[0],
-                      static_cast<int>(len));
+                      wstr.data(),
+                      static_cast<int>(wstr.length()));
   return wstr;
 }
 
@@ -167,8 +167,8 @@ std::string FromWinWide(const std::wstring& wstr) {
                       0,
                       wstr.c_str(),
                       static_cast<int>(wstr.length()),
-                      &str[0],
-                      static_cast<int>(len),
+                      str.data(),
+                      static_cast<int>(str.length()),
                       NULL,
                       NULL);
   return str;
@@ -208,7 +208,7 @@ std::string NormalizeFilename(const std::string& filename) {
     return std::string();
   }
 
-  CharUpperBuffW(&wideString[0], static_cast<int>(wideString.length()));
+  CharUpperBuffW(wideString.data(), static_cast<int>(wideString.length()));
   return FromWinWide(wideString);
 #else
   std::string normalizedFilename;

src/api/plugin.cpp

@@ -204,7 +204,7 @@ size_t Plugin::GetOverlapSize(
 
   size_t overlapSize = 0;
   auto ret = esp_plugin_records_overlap_size(
-      esPlugin.get(), &esPlugins[0], esPlugins.size(), &overlapSize);
+      esPlugin.get(), esPlugins.data(), esPlugins.size(), &overlapSize);
   if (ret != ESP_OK) {
     throw FileAccessError("Error getting overlap size for \"" + name_ +
                           "\". esplugin error code: " + std::to_string(ret));

src/api/sorting/group_sort.cpp

@@ -269,7 +269,7 @@ std::vector<Vertex> GetGroupsPath(const std::vector<Group>& masterlistGroups,
       boost::weight_map(edge_map_t(weightMap))
           .predecessor_map(boost::make_iterator_property_map(
               predecessors.begin(), get(boost::vertex_index, graph)))
-          .distance_map(&distance[0])
+          .distance_map(distance.data())
           .root_vertex(toVertex));
 
   std::vector<Vertex> path;