Changes to googlearth library

[mikesamar]

Dear developers of Google Earth library,

I made some changes to your Google Earth library for Google Maps API version 3. Maybe these are good suggestions for more users of this library.

The following changes I made:

• Option to show the Google Earth map type button or not. Extra parameter to the function GoogleEarth.
  Not all users want to give visitors the choose to change the maptype.
  
• The library changes the defined maptypes and set them to the defaults and add Google Earth.
  I made a change (not completly correct) so that defined maptypes outside the library are saved and google earth is added.
• To find the maptypecontrol I added the other maptypes because the google earth control doesn't have to be added.
  
• I needed to change the library to check if the maptype control for google earth is defined. If not some styling can't be done (z-index of the maptypecontrol, etc.).

I've added the change library.

I hope these proposed changes are a good addition to the library.

If you have questions, please let me know.

Best regards,

Mike