- Add "thr_" prefix to thread utility functions
- Compare threadid_ts in a portable manner, where possible

  * Rename everything.
    * Strip J prefix.
    * Change UpperCamelCase functions to lowerCamelCase.
  * Remove global (!) semaphore count mutex on OSX.
  * Remove semaphore count getter (unused, unsafe, depended on internal
    API functions on Windows, and used a hack on OSX).
  * Add `Atomic<type>`.
  * Make `Thread` handle thread names.
  * Add support for C++11 multi-threading.
  * Combine pthread and win32 sources.
  * Remove `ThreadStarted` (unused, unneeded).
  * Move some includes from the headers to the sources.
  * Move all of `Event` into its header (allows inlining with no new includes).
  * Make `Event` use `Semaphore` (except on Windows).
  * Move some porting functions into `Thread`.
  * Integrate logging with `Thread`.
  * Add threading test.

Also, clean up surrounding code style
Replace by-value parameter passing with const refs when possible
Fix post-increment of iterators

Move debug streams to log.cpp|h

Move GUI-related globals to clientlauncher

Move g_settings and g_settings_path to settings.cpp|h

Move g_menuclouds to clouds.cpp|h

Move g_profiler to profiler.cpp|h

For usages of assert() that are meant to persist in Release builds (when NDEBUG is defined), replace those usages with persistent alternatives

Pass drawtype and material type to shaders.
Move shaders generation to startup only.
Allow assign shaders per tile.
Initial code to support water surface shader.

Parallax mapping with slope information.
Overriding normal maps.

Fix Result of processed Request was written to invalid (non existent) ResultQueue if requesting thread timed out before

Also write something about rebuilding shaders to infostream in
Client::afterContentReceived()