MGR: same as previous commit.
MGR: Setup an assert handler under the wxWidgets 3.x framework, log output to the log file on release builds.
MGR: Hookup wxWidgets 3.0 diagnostics framework, redirect asserts to stderr.
MGR: Remove what are now over active asserts complaining about pConfig being NULL.  Apparently we knew already knew that pConfig could be NULL in certain circumstances and followed up with a check to return from the function if pConfig was NULL, that code was added in 2007.  The assert check wasn't really needed after that point.
MGR: Update BOINC icon set to v5.
MGR: If an assert is thrown while running under a debugger, break into the debugger.
MGR: Re-introduce the OnEndSession event handler.
- Tag for 7.3.9 release
  client_release/7.4/7.3.9
MGR: Only dump a crash report if wxUSE_DEBUGREPORT is defined in wxWidgets.
MGR: Get assert handler working on Macintosh to log output to the log file on release builds.
 - Fix build break on Mac: wxUSE_DEBUGREPORT is defined as 1 even though wxDebugReport() is not available in wxCocoa built from wxCocoa.xcodeproj.
MGR: We need to cast mb_str() calls when using fprintf or some other C Runtime function.
MGR: Remove dead code
MGR: Fix single instance detection so that it is compatible with Fast User Switching on Windows and Mac.  We are now using wxSingleInstanceChecker which should be compatible on all platforms.
server: store and display gpu_active_frac

- gpu_active_frac is the fraction of time GPU use is allowed
  while the client is running.
  Previously the client reported it but we weren't storing it in the DB.
  We may need it in the future for batch scheduling logic.
- fix a crashing bug in scheduler
- client: minor message tweak
MGR & Client: Massive code clean-up.  Remove as much of the LoadLibrary/GetProcAddress stuff as we can under VS 2012.
Merge branch 'master' of ssh://isaac.ssl.berkeley.edu/boinc-v2
WINBUILD: Update to 7.3.9
client: Fix the CPUID calls for structured extension feature flags, it was clobbering standard support flags on Windows.
LIB: Introduce the notion of per-user account log files.  Setup the manager, tray applet, and screen saver to use per-user account log files. Technically the default screen saver should be as well.

Log Locations:
WIN   : %APPDATA%\BOINC
MAC   : $(HOME)/Library/Logs/BOINC
Linux : $(HOME)/.BOINC
- Tag for 7.3.10 release
  client_release/7.4/7.3.10
server: use gpu_active_frac in scheduling decisions

On some hosts, gpu_active_frac may be much less than active_frac
(i.e., GPUs may be available much less than CPUs).
Use gpu_active_frac in the following places:

- scheduler: in estimating the elapsed time of jobs,
    to decide whether they can meet deadline
- scheduler: in computing the effective speed of a (host, app version),
    when deciding what size class it belongs to
- size_census: in computing effective speed of (host, app versions)

(Previously, we were just using active_frac in all these cases)