Visual Studio 2013 support + strtof + inline

- VC12 has better C99 library support due to C++11
- defined strtof for VC11 or older
- define "inline" only if the C compiler is used
include inttypes.h if _MSC_VER is not defined
Merge pull request #1311 from cremno/msvc-2013-support

Visual Studio 2013 support (and two other fixes)