#808 Select first valid compiler as default

[bluehazzard]

In the forum were reports about invalid default compiler.
There was a valid gcc compiler and an invalid intel compiler. The intel compiler was selected as default and the invalid compiler warning poped up.
The default compiler should always be a valid compiler.
Expected behaviour: If the default compiler is invalid, go trought the compiler list and select the first valid compiler.

[Andrew Cottrell]

I think that on the first time CB is executed the "Compiler auto detection" dialog that is displayed should default to the first detected compiler.
On Windows 10 with Cygwin and MSYS (mingw64) installed the dialog shows:
1) Only the Cygwin is detected
2) The "GNU GCC compiler" compiler is "Not Found"
3) BUT the default is "GNU GCC compiler", which is crazy

If CB is changed to default on the first time it is executed then it should fix the issues with noobs.

Changing the compiler after this to correct a compiler setup or config could cause more problems than it fixes. For example if you load a project that was setup for Cygwin on Linux and you have configured the default compiler to be the second or sub sequence compiler i the list then you do not want CB to update the project to use the first compiler. It is better to leave the project with an invalid compiler and let the dev fix it manually.

[Andrew Cottrell]

The changes that I have done for ticket 1117 may resolve this w.r.t. not allowing the end user to select an invalid compiler.