avr.cfg: Added support for more functions.
Many platforms don't support backtraces. Fix compile for Solaris platform.

This change was tested with Solaris 10 on X86 and SPARC.

More information on Unix Backtrace Support
 - http://www.gnu.org/software/libc/manual/html_node/Backtraces.html

It is not supported on the following platforms:
 - https://www.gnu.org/software/gnulib/manual/html_node/execinfo_002eh.html

        Mac OS X 10.3,
        FreeBSD 6.0,
        NetBSD 5.0,
        OpenBSD 3.8,
        Minix 3.1.8,
        AIX 5.1,
        HP-UX 11,
        IRIX 6.5,
        OSF/1 5.1,
        Solaris 10,
        Cygwin,
        mingw,
        MSVC 9,
        Interix 3.5,
        BeOS.
Speedup checking large amounts of arrays (#5615) by avoiding Token::Match calls in CheckBufferOverrun::checkScope(2).
-> Decreased entire checking time on a subset of the attached file by 66% (MSVC12, x64, non-matchcompiled)
Refactorizations optimizing std::string usage:
1) Added global static const std::string emptyString; object:
-> Replaces some static variables in functions which might be not threadsafe
-> Avoids constructor call (std::string::string(""))
-> Even functions that return an empty string in some branches can return by reference now.
Added to config.h to ensure that it is available everywhere

2) Added overloads for TestFixture::assertEquals for the most common use cases:
-> Moves conversion from const char[] to std::string into a function, reducing code duplication in binary.
Store Token::_originalName on heap, since it is only used for a small amount of Tokens (reduce memory usage of TokenList by ~12% (x64))
avr.cfg and posix.cfg: Added support for more functions.
AST: fixed ast for '++i;'
CheckBufferOverrun: Added bufferOverrun2 that is based on ValueFlow/SymbolDatabase/Ast from the start. Replaced some old checking.
Fix some compiler warnings
CheckBufferOverrun: Removed old for-loop handling. This is handled through ValueFlow from now on.
Simplify defines.
Merge pull request #350 from lasergnu/stacktrace

Many platforms don't support backtraces. Fix compile for Solaris platform
Ticket #5952: Simplify redundant parentheses in pointer variable declarations.
Fixed #5931 (arrayIndexOutOfBoundsCond id reported instead of arrayIndexOutOfBounds)
Library: Handle FIlE_NOT_FOUND better
Fixed #5861 (valueFlowSubFunction: fp for float value)
Improve error message for Windows SEH adding more details if available
Merge pull request #351 from simartin/ticket_5952

Ticket #5952: Simplify redundant parentheses in pointer variable declarations
Try to fix configuration of un*x signal handling and backtrace support
Fixed #5850 (Wrong Message on self assignment)