Bugfix for Travis

TODO.md

 ## Bugs
 
 * Screenshots are sometimes not written, sometimes distorted?
-* imgui integration still very much unfinished
-    * toggling with ‘q’ means one can’t use input ‘q’ into a text field
-    * clicking outside of the debug window does nothing
 
 ## Cmake
 

src/FontManager.cpp

     add(new FontSDL(), ".ttf");
 #endif
 
+    mFontInit = false;
     font = -1;
 }
 
     if (font == -1)
         return -1;
 
+    mFontInit = true;
     fonts.at(font)->setFont(mFontName);
     return fonts.at(font)->initialize();
 }

src/UI.cpp

     ImGuiIO& io = ImGui::GetIO();
     io.DisplaySize = ImVec2((float)getWindow().getWidth(), (float)getWindow().getHeight());
 
-    static long lastTime = 0;
+    static unsigned long lastTime = 0;
     io.DeltaTime = ((float)(systemTimerGet() - lastTime)) / 1000.0f;
     lastTime = systemTimerGet();
+    if (io.DeltaTime <= 0.0f)
+        io.DeltaTime = 1.0f / 60.0f;
 
     ImGui::NewFrame();
 
 }
 
 void UI::handleText(char *text, bool notFinished) {
+    if (notFinished)
+        return;
+
     ImGuiIO& io = ImGui::GetIO();
     while (*text != '\0') {
         io.AddInputCharacter(*text);