Update to cxxopts 3.0

--- a/meson.build
+++ b/meson.build
@@ -40,7 +40,7 @@ if cpp_compiler.get_id() == 'msvc'
   message('Applying workaround for MSVC by adding flag /Zc:twoPhase-: https://stackoverflow.com/questions/56782470/why-do-i-have-warning-c4199-two-phase-name-lookup-is-not-supported-for-c-cli')
 endif
 
-cxxopts_dep = dependency('cxxopts', fallback : ['cxxopts', 'cxxopts_dep'])
+cxxopts_dep = dependency('cxxopts', version : '>=3.0', fallback : ['cxxopts', 'cxxopts_dep'])
 eigen3_dep = dependency('eigen3', fallback : ['eigen', 'eigen_dep'])
 openmp_dep = dependency('openmp', required : false)
 
diff --git a/src/exe/cmcavity.cxx b/src/exe/cmcavity.cxx
index 427d3c0..3a5c747 100644
--- a/src/exe/cmcavity.cxx
+++ b/src/exe/cmcavity.cxx
@@ -41,7 +41,7 @@ void PrintHeaderAddon(std::ostream &outputStream) {
 // MAIN PROGRAM STARTS HERE
 /////////////////////////////////////////////////////////////////////
 
-int main(int argc, char *argv[]) {
+int main(const int argc, const char *argv[]) {
   // Handle obsolete arguments, if any
   for (int i = 0; i < argc; i++) {
     std::string opt = argv[i];
@@ -451,7 +451,7 @@ int main(int argc, char *argv[]) {
 
       logFile.close();
     }
-  } catch (const cxxopts::OptionException &e) {
+  } catch (const cxxopts::exceptions::exception &e) {
     std::cout << "Error parsing options: " << e.what() << std::endl;
     return 1;
   } catch (RbtError &e) {
@@ -463,4 +463,4 @@ int main(int argc, char *argv[]) {
   _RBTOBJECTCOUNTER_DUMP_(std::cout)
 
   return 0;
-}
\ No newline at end of file
+}
diff --git a/src/exe/cmdock.cxx b/src/exe/cmdock.cxx
index 10e18ca..86bbff1 100644
--- a/src/exe/cmdock.cxx
+++ b/src/exe/cmdock.cxx
@@ -80,7 +80,7 @@ void printHelpFooter() {
 // MAIN PROGRAM STARTS HERE
 /////////////////////////////////////////////////////////////////////
 
-int main(int argc, char *argv[]) {
+int main(const int argc, const char *argv[]) {
   // Handle premature termination
   signal (SIGINT, terminator);
   
@@ -941,7 +941,7 @@ int main(int argc, char *argv[]) {
     log << "Thank you for using " << Rbt::GetProgramName() << " "
               << Rbt::GetVersion() << "." << std::endl;
     logFile.close();
-  } catch (const cxxopts::OptionException &e) {
+  } catch (const cxxopts::exceptions::exception &e) {
     std::cout << "Error parsing options: " << e.what() << std::endl;
     return 1;
   } catch (RbtError &e) {
@@ -953,4 +953,4 @@ int main(int argc, char *argv[]) {
   _RBTOBJECTCOUNTER_DUMP_(std::cout)
 
   return 0;
-}
\ No newline at end of file
+}
diff --git a/src/exe/cmmoegrid.cxx b/src/exe/cmmoegrid.cxx
index 4bff8f3..bf74b52 100644
--- a/src/exe/cmmoegrid.cxx
+++ b/src/exe/cmmoegrid.cxx
@@ -57,7 +57,7 @@ RbtModelList CreateProbes(std::string anAtomTypeStr) {
 // MAIN PROGRAM STARTS HERE
 /////////////////////////////////////////////////////////////////////
 
-int main(int argc, char *argv[]) {
+int main(const int argc, const char *argv[]) {
   std::cout.setf(std::ios_base::left, std::ios_base::adjustfield);
 
   // Strip off the path to the executable, leaving just the file name
@@ -268,7 +268,7 @@ int main(int argc, char *argv[]) {
       }
       std::cout << "done." << std::endl;
     }
-  } catch (const cxxopts::OptionException &e) {
+  } catch (const cxxopts::exceptions::exception &e) {
     std::cout << "Error parsing options: " << e.what() << std::endl;
     return 1;
   } catch (RbtError &e) {
diff --git a/src/exe/cmzip.cxx b/src/exe/cmzip.cxx
index 1d1f69a..043d7be 100644
--- a/src/exe/cmzip.cxx
+++ b/src/exe/cmzip.cxx
@@ -504,7 +504,7 @@ void rescue(cxxopts::ParseResult result){
 }
 
 // ENTRY POINT
-int main(int argc, char *argv[]) {
+int main(const int argc, const char *argv[]) {
   // Handle premature termination
   signal (SIGINT, terminator);
 
@@ -580,7 +580,7 @@ Use this if CmDock terminates prematurely. CmZIP will search for records in the
       return 0;
     }
 
-  } catch (const cxxopts::OptionException &e) {
+  } catch (const cxxopts::exceptions::exception &e) {
     std::cout << "Error parsing options: " << e.what() << std::endl;
     return 1;
   } catch (const std::exception &exc) {
@@ -589,4 +589,4 @@ Use this if CmDock terminates prematurely. CmZIP will search for records in the
   /*} catch (...) {
       std::cout << "Unknown exception" << std::endl;
   }*/
-}
\ No newline at end of file
+}