Remove GIL to avoid deadlocks when calling CEF functions

[GoogleCodeExporter]

In the pxd file, function needs to be defined as "nogil". In the pyx file the call must use the "with nogil" statement.

From Cython's documentation:

Note that acquiring the GIL is a blocking thread-synchronising operation, and therefore potentially costly. It might not be worth releasing the GIL for minor calculations. Usually, I/O operations and substantial computations in parallel code will benefit from it.

Revision ec1ce78 removes the GIL lock from the following calls: Initialize(), Shutdown(), CreateBrowserSync(), SetOsModalLoop(), QuitMessageLoop(), CefExecuteProcess().

Keeping this issue Open, as there still might be some functions from which the GIL lock should also be removed.

Original issue reported on code.google.com by czarek.t...@gmail.com on 8 Jan 2014 at 11:15

[cztomczak]

Add GIL section to Contributing-code.md document in commit a5d97f0.