Add the --git-branch <branch> command

It is often useful to be able to specify another branch than the current
one; let's not require switching branches.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

src/gource.cpp

@@ -50,6 +50,7 @@ void gource_help(std::string error) {
     printf("  -e, --elasticity FLOAT               elasticity of nodes\n");
     printf("  -b, --background FFFFFF              background colour in hex\n\n");
 
+    printf("  --git-branch                         specify another branch than the current one\n");
     printf("  --git-log-command                    print the git-log command used by gource\n");
     printf("  --cvs-exp-command                    print the cvs-exp.pl log command used by gource\n\n");
 

src/main.cpp

@@ -49,6 +49,19 @@ int main(int argc, char *argv[]) {
             exit(0);
         }
 
+        if(args == "--git-branch") {
+
+            if((i+1)>=arguments.size() || arguments[i+1].size() == 0) {
+                gource_help("specify a git branch");
+            }
+
+            gGourceGitLogCommand += " ";
+            gGourceGitLogCommand += arguments[++i];
+
+            continue;
+        }
+
+
         if(args == "--cvs-exp-command") {
             printf("%s\n", gGourceCvsExpLogCommand.c_str());
             exit(0);