Config Planner - Choose how to access the map tiles : server, cache or both

[Godeffroy]

• Add ComboBox in ConfigPlanner to choose if map is loaded from cache only, server only or cache and server (default). This setting is saved in the config.xml

• Add button in ConfigPlanner to Open Map Cache Folder

• SRTM files are downloaded if GMaps Access Mode is not CacheOnly

This greatly reduces cpu load and unnecessary network access in case of using an offline GCS.

I don't know if i need to modify all ConfigPlanner.resx file's language as well ?

[EosBandi]

• Is there any reason why not simple check if we have network connectivity and set the mode based on the result ? A permanent setting has a risk that user forgot it in offline mode and expects that once connected to a network it will download srtm/maptiles.
• There are already an "Age Map" function in the ctrl-f screen, if a user really want to delete the whole cache (including the database) then he/she must know where to find it :) Even if it needed, the the right place to put it is the ctrl-f screen, alongside with the other housekeeping and experimental functions.

[Godeffroy]

Thanks for you response !
I plan to do another PR on the prefetch feature to make it faster, i can also add this : before prefetching, it switch whatever mode it is to ServerAndCache ?
And another PR on the inject GE as it will be possible to easily inject png, jpeg and jpg with a progress bar, change map provider to custom and map access mode to CacheOnly.

[Godeffroy]

Rebased on master