remove explicit specification of compiler, which was inconsistent anyway, and now Xcode will use its default, which of course depends on which version of Xcode you use
don't specify SDK at target level since it's already specified at project level
don't specify GNU C99 dialect in 2/3 targets when project level specifies standard C99
don't redundantly specify GCC_PRECOMPILE_PREFIX_HEADER at target level when it's set at project level
don't redundantly specify GCC_OPTIMIZATION_LEVEL at target level when it's set at project level
specify GCC_DYNAMIC_NO_PIC at project level, not 3 times in each target
some targets were linking to system frameworks by specifying them in OTHER_LDFLAGS, some added to the project. Some linked to Cocoa some to Foundation and AppKit. Made everything nice by never using OTHER_LDFLAGS and always linking to the minimal frameworks necessary.
specify DWARF preference at project level, and don't both with dwarf-with-dsym for App-Release since since app isn't really being distributed to anyone, it's just a test app
Set ALWAYS_SEARCH_USER_PATHS=YES at project level, never set it to NO in any target
removed long obsolete ZERO_LINK setting
removed long obsolete ZERO_LINK setting
removed obsolete GCC_MODEL_TUNING which is only for PPC and was only set in test app and unit tests anyway
don't bother specifying GCC_ENABLE_OBJC_EXCEPTIONS = YES as it's been default for a long time
enabled some more compiler warnings, some of which need newer Xcodes but are harmless in older versions
fix warning from clang ToT: don't compare NSStrings with ==, use isEqualToString:
use import instead of include
as a matter of style, replaced realloc with reallocf, to prevent memory leak
enabled more warnings, again only available in newer Xcodes, but harmless in older ones
Merge pull request #24 from seanm/master

cleanup of Xcode project
Changed all targets to inherit prefix file from project settings