Added better version information

Added better version information

The current version is now held in src/version.cc in a number of defines which needs to be modified when changing version.

The following defines make up the version information:

  MAJOR_VERSION
  MINOR_VERSION
  BUILD_NUMBER
  PATCH_LEVEL
  CANDIDATE_VERSION

The first four are numbers and the fifth is a boolean. Besides these five the define

  SONAME

can be used to set a specific soname when building the a shared library (see below). This will most likely be used on stable branches where binary compatibility is ensured between different versions. This define is a string.

This version information is now read by the SCons build to support setting the soname for a Linux shared library. This requires passing the option soname=on to the SCons build.

When soname=on is specified the soname for the shared library can be set in two different ways. Either it will be the full versioned library name (e.g. libv8-1.2.2.so) or a specific soname defined in src/version.cc. Whenever a shared library is build with an soname the filename of the library will hold the full version name (e.g. libv8-1.2.2.so).

I did not update the xcode project with the new files.

BUG=151
Review URL: http://codereview.chromium.org/100104

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1826 ce2b1a6d-e550-0410-aec6-3dcde31c8c00