Change Log 7.6.17 - 7.6.18 (December 1, 2015)

Preliminary Change Log 7.6.17 -> 7.6.18

• Mac: Add sched_msgs.cpp,.h to target libboinc in Xcode project.
• Mac scr: add change I omitted from my commit d3071cd: build 32-bit and 64-bit fat binary for compatibility with OS 10.6 and OS 10.7. This requires building with Xcode 5 or earlier, because Xcode 6 forces converting to ARC, which does not support 32-bit binaries.
• lib: fix resource leak.
• lib: add descriptions for new error numbers.
• mgr: replace strncpy with strlcpy.

• strlcpy always null terminates the dest buffer, strncpy doesn't when the buffer is too small.

• Mac: Revert my commit 385f1e5: remove sched_msgs.cpp, *.h from target libboinc in Xcode project because commit ea7edd7 (which moved these files from sched/ to lib/) has not yet been ported to this branch from master.
• Mac: Modify Xcode project to allow all third party libraries to be accessed either directly or through symbolic links
• Mac: Modify build script to allow building Screensaver with Xcode 6 or later. It will build as "Fat" 32-bit / 64-bit binary with Garbage Collection under Xcode 5 and earlier (for backward compatibility to OS 10.6) or as 64-bit only binary with Automatic Reference Counting under Xcode 6 or later. Xcode 6 and later won't build objective-C sources with GC and so will build screensaver only as a 64-bit binary.
• Mac: Update script for compatibility with Travis-CI:

• Allow putting third party packages in ../mac3rdParty/ as an alternative to putting them in a parent directory. • If the packages are placed in the parent directory, this script creates symbolic links to them in ../mac3rdParty/. • Return an error code indicating which build failed (or 0 if all OK.)

• Mac: Update Xcode project for compatibility with Travis-CI: expect third party packages (or symbolic links to them) to be in ../mac3rdParty directory.
• Mac: new script to allow building with Travis-CI.
• client (linux): remove -n 7 in ionice call.
• client (Win): lowering I/O priority is an option rather than the default.

• Apparently even the thread-level version (SetThreadPriority()) caused the client to starve and become unresponsive if something else was doing lots of disk I/O.

• client: fix bug in GPU detection.
• client(unix): fix VirtualBox detection.