Implemented new feature activable with CLI and changed OpenGL debug mode CLI option
Implemented new feature activable with CLI and changed OpenGL debug mode CLI option

The OpenGL debug mode command line option has been changed from '-debug' to '--debug-ogl'.

New features activable whit CLI

The idea is to be able to implement and test/use new code without stripping off the current one.
These features/new code will be in the released stuff, but unavailable until explicitly requested.

The new features which are under development can be enabled using the 'new_features.def' file.
This file is a plain text file with one feature to enable a line.
The file is parsed and each feature is added to the builtins using the pattern 'mcenf_<feature>'.
The value for these builtins is 'True'.
Then, in the code, just check if the builtins has the key 'mcenf_<feature>' to use the new version of the code:

```
def foo_old():
    # Was 'foo', code here is the one used unless the new version is wanted.
    [...]

def foo_new():
    # This is the new version of the former 'foo' (current 'foo_old').
    [...]

if __builtins__.get('mcenf_foo', False):
    foo = foo_new
else:
    foo = foo_old

```

Khroki/MCEdit-Unified,fhfuih/MCEdit-Unified,fhfuih/MCEdit-Unified,fhfuih/MCEdit-Unified,Khroki/MCEdit-Unified,Khroki/MCEdit-Unified